I was just thinking about the fairy tale characters' real world counterparts, and I noticed that most of them had names that tied into their "real," fairy tale selves. So I decided to throw together a list of their names, with meanings and explanations, just for kicks. First I will say what the character's name is in fairy tale land, then in the real world, with meaning attached. All name meanings come from the website Behind the Name, with help from Wikipedia.

I will add more characters when they are introduced and edit existing characters when we know their full names and/or know more about them.

Character: Snow White
Real World Counterpart: Mary Margaret Blanchard
-Meaning of:
--Mary: Derived from the Hebrew name "Miryam," it's not known for certain what this name means, but Behind the Name lists several popular theories: "sea of bitterness," "rebelliousness," "wished for child," "beloved" or "love." All of these could possibly apply to Snow White/Mary Margaret; "rebelliousness" because this version of SW looks to be much spunkier and more independent than others; "wished for child" because she had to give her child up and has never given up hope to see her again, even if it's only a subconscious hope; "beloved" because she is loved by Prince Charming; and "love," both because of Charming's love for her, and for her love for all living things (well, except maybe the Evil Queen). "Bitterness" is a bit harder, because she hasn't shown much bitterness towards anyone as of yet, but as we get to know her better, we may see that side of her. I'm sure she'll be bitter towards the Queen after she remembers who is and what the Queen did to everyone!
--Margaret: "Margaret" is derived from the Latin name "Margarita," which is derived from the Greek "margarites," meaning "pearl."
--Mary Margaret: IMDb user Dledee pointed out that the name Mary Margaret could possibly be a reference to the 17th century historical figure Maria Sophia Margaretha Catherina von Erthal, who, it is theorized, may have been the basis for the fairy tale and character Snow White. "Mary" is the English form of "Maria" and "Margaret" is the English form of "Margaretha," so this is quite likely. Thanks to Dledee for the tip!
--Blanchard. This is the easiest, I didn't even have to look it up. The surname "Blanchard" is derived from the name "Blanche," which is the French word for "white" (thank you, A Streetcar Named Desire!) As in, Snow White.

Character: Regina
Real World Counterpart: Regina Mills
--Regina: "Regina" is a Latin name meaning "queen." No further explanation required. It is worth noting that Regina is the only character (besides Emma, of course) whose name is the same in the fairy tale land and the real world. This is probably because she was the one who cast the curse, and so is exempt from it.
--Mills: This used to be a surname given to someone who either worked in a mill or lived near one, so at first, it doesn't sound like it holds any significance to the Evil Queen/Regina, but Fanpopper Haleysoltau rather brilliantly pointed out that, as Regina has never married, "Mills" is most likely her father's surname, making her Mills' daughter. This does not seem significant until you remember that the Evil Queen made a deal with Rumpelstiltskin, who, in the fairy tale sharing his name, struck a similarly Faustian deal with the miller's daughter. This suggests that the Evil Queen is perhaps not so evil as she seems, just a desperate woman who made an unfortunate deal in the heat of the moment, like the miller's daughter or this show's version of Cinderella. Full credit for the idea goes to Haleysoltau. Thanks, Haley!

Character: James, aka Prince Charming
Real World Counterpart: David Nolan, aka John Doe
-- James: "James" is a form of the name "Jacob," which was itself derived from the Hebrew name "Ya'aqov," meaning "holder of the heel" or "supplanter." Another possible theory is that the name Jacob is derived from the Hebrew name "Ya'oqov'el," meaning "may God protect." So far, the last meaning seems to be most applicable to our Prince Charming: "may God protect" could have to do with the fact that he's a very good good guy, so it's extra important for someone as good as he to have protection from a higher authority.
--David: "David" is derived from the Hebrew name "Dawid," which was probably derived from Hebrew "dwd," meaning "beloved." Hmm, what other real world character has a name meaning "beloved"? That's right, Mary Margaret, the real world counterpart of Snow White, and James/David's true love. Coincidence? I think not. As shanabelle pointed out, there was also a very famous Jewish king, King David, who had a wife named Abigail. The very same name as James' former fiancee! Thanks, shanabelle!
--Nolan: "Nolan" is an Irish surname derived from "Ó Nualláin," which means "descendant of Nuallán." "Nuallán" is derived from the Irish nuall, meaning "noble, famous." This would definitely fit David, being that he is not only a prince and so a member of the nobility, but a very noble, honorable person.

Character: Abigail
Real World Counterpart: Kathryn Nolan
--Abigail: "Abigail" is derived from the Hebrew name "'Avigayil," meaning "my father is joy." We know nothing about her father as yet, but it's to be assumed that he is the king of the kingdom neighboring James' father's, so I have a couple theories. One, he may be a super nice guy and all-around great dad; and two, maybe it's just the joy of having a king for your father, thus making you a princess. This second one seems like it could apply to Abigail, due to how spoiled and snobbish she is. Fanpopper shanabelle also pointed out that "Abigail" was the name of one of King David's wives. Our Abigail was the fiancee of Prince James in the fairy tale world, and the wife (as Kathryn) of David (James) in the real world. Thank you for the tip, shanabelle!
--Kathryn: "Kathryn" is a variant of the English name "Katherine," which is derived from the Greek name "Aikaterine," the etymology of which is debated. It could derive from the earlier Greek name "Hekaterine," which came from the Greek word hekateros, meaning "each of the two"; it could derive from the name of the Greek goddess Hecate; it could be related to the Greek word aikia, meaning "torture"; or it could come from a Coptic name meaning "my consecration of your name." It later became associated with the Greek word katharos, meaning "pure." A couple of these meanings could fit Kathryn Nolan; "each of the two" would jive with her allegedly being David's wife, and "torture" is very fitting, as being separated from his one true love and married to someone he dislikes is part of the curse.
--Nolan: See "David Nolan."

Character: Rumpelstiltskin
Real World Counterpart: Mr. Gold (first name not yet revealed)
-Meaning: This one doesn't take a genius. In the fairy tale "Rumpelstiltskin," Rumpelstiltskin spins straw into gold for the miller's daughter (for a price...). We don't know what his first name is yet.

Character: Little Red Riding Hood
Real World Counterpart: Ruby (surname not yet revealed)
-Meaning: Another easy one. A ruby is a red-colored gemstone. We don't yet know what her and her Granny's surname is. Speaking of Granny...

Character: Granny (real name not yet revealed)
Real World Counterpart: Granny (see above)
-Meaning. Uh, yeah.

Character: Jiminy Cricket
Real World Counterpart: Archie Hopper
--Archie: Here's one where my insatiable devouring of fiction comes in handy: there's a great old newspaper comic series which began in 1916 called "archy and mehitabel" (yes, all lowercase), and it's about the adventures of two best friends, Archy, a cockroach who is a newspaper columnist (not to mention a free verse poet in a previous life), and Mehitabel, an alley cat. Yes, Jiminy Cricket was, well, a cricket, not a cockroach, but close e-frakking-nough, in my opinion. I don't think it's a coincidence that the human version of an insect has the same name of an insect who had been human in a past life. It's simply not in the realm of possibility! But if you don't buy that, for some crazy reason, let's talk about the meaning of the name "Archibald," which I'm sure "Archie" is short for. "Archibald" is a Germanic name meaning "genuine" and "bald." The former could quite possibly tie in with his aversion to telling lies, and as for the latter, well, he does have a bit of a receding hairline.
--Hopper: Hopping? You know, like a cricket?

Character: the Huntsman (name not revealed)
Real World Counterpart: Sheriff Graham (first name not revealed)
-Meaning: "Graham" is from a Scottish surname, which was in turn derived from an Old English place name meaning "gravelly homestead." Not sure what the significance of this would be.

Character: Gepetto
Real World Counterpart: Marco (surname not given)
-Meaning: "Marco" is the Spanish and Italian form of the name "Mark." BTN doesn't give a meaning for "Mark," but the comments alternate between "that of a god," "warrior of God" and "heavenly," so there's a good chance it has something to do with God. I'm probably reaching here, but might this tie in with Gepetto playing God by making a real, live son? Possibly? Also, both Gepetto and Marco are Italian names, so... yeah.

Character: Gretel
Real World Counterpart:
--Gretel: The German name "Gretel" is a diminutive of the name "Grete," which is itself the short version of "Margaret." For the definition of "Margaret," see Snow White's entry.
--Ava: "Ava" is a name from a few different cultures, with each culture attaching a different meaning to the name, so I'll focus on the two that I think are relevant. The German name "Ava" was a short form of Germanic names beginning with the element avi, possibly meaning "desired." Could this relate to Hansel and Gretel being wanted by their father, even though their stepmother wanted to get rid of them? The second version of this name is the English "Ava," a variant of "Eve." "Eve" is derived from the Hebrew name "Chawwah," which was derived from the Hebrew words chawah, meaning "to breathe," or the related word chayah, "to live." Of these two names, I'd say the first is more relatable to Gretel/Ava, partly because that version is a German name and "Hansel and Gretel" is a German fairy tale.
--Zimmer: "Zimmer" is a common German surname, from "zimmermann," which is German for "carpenter." Makes sense for Ava and Nicholas to have a German surname, as "Hansel and Gretel" is a German fairy tale.

Character: Hansel
Real World Counterpart: Nicholas Zimmer
--Hansel: "Hansel" is the diminutive form of the German name "Hans," which is the German form of "Johannes," which is a form of the English name "John." This name is derived from the Latin name "Iohannes," from the Greek name "Ioannes," which itself is derived from the Hebrew name "Yochanan," meaning "YAHWEH (God) is gracious."
--Nicholas: "Nicholas" is from the Greek name "Nikolaos," meaning "victory of the people."
--Zimmer: See "Gretel/Ava Zimmer."

Character: Hansel and Gretel's father
Real World Counterpart: Michael
--Michael: "Michael" is from the Hebrew name "Mikha'el," meaning "who is like God?"

Character: The Blind Witch (real name not given)
Real World Counterpart: Ms. Ginger
--Ginger: Ginger is a spice, one which is the key ingredient in gingerbread. And of what was the witch's cottage made? Gingerbread.

Character: Cinderella
Real World Counterpart: Ashley Boyd
--Ashley: From an English surname which was itself derived from an Old English place name meaning "ash tree clearing." We all know Cinderella was given that nickname due to her habit of sitting among the cinders (ashes) in the fireplace, so the name "Ashley" is quite fitting.
--Boyd: "Boyd" is a Scottish surname, possibly derived from the island of Bute's name. Doesn't appear to have much significance.

Character: Prince Thomas
Real World Counterpart: Sean
--Thomas: "Thomas" is the Greek form of the Aramaic name "Ta'oma'," which means "twin." Possibly a reference to Thomas' fabricated story of Ella expecting twins?
--Sean: "Sean" is a form of the name "John," which is derived from the Hebrew name "Yochanan," meaning "YAHWEH (God) is gracious." Doesn't appear to have much direct significance to the character.

Character: The Magic Mirror (no real name)
Real World Counterpart: Sidney Glass
--Sidney: "Sidney" is originally derived from various places in England meaning "wide island," from Old English. This doesn't appear to have much connection to the character; the main connection is that Sidney works for the newspaper "The Daily Mirror." Get it? Mirror?
--Glass: I really don't think I have to explain this one, but mirrors were originally called "looking glasses." Fairly obvious connection.

Character: Grumpy
Real World Counterpart: Leroy (surname not yet revealed)
-Meaning: Hmmm... the name "Leroy" comes from the French "le roi," meaning "the king." This one doesn't fit, unless we take into account that Grumpy was a member of the War Council, and even then, the connection is tenuous at best.

Character: Sleepy
Real World Counterpart: Walter
-Meaning: "Walter" is a Germanic name meaning "ruler of the army." As with Grumpy/Leroy, this doesn't make much sense unless you remember that Sleepy was on the War Council, and even then....

Character: Belle
Real World Counterpart: Name unknown
-Meaning: "Belle" is the French word for "beautiful," which is fitting, considering Belle is the protagonist of the fairy tale "Beauty and the Beast" (La belle et la bête). This was also the name of the "beauty" in the classic Disney movie Beauty and the Beast.

Character: Maurice
Real World Counterpart: Mo French
--Maurice: I'm not sure if his name was actually mentioned in the episode, but Belle's father was named Maurice in the Disney movie Beauty and the Beast, and considering most of the characters are named for their Disney counterparts, it makes sense that this would be his name. This name is derived from the Roman name "Mauritius," itself a derivative of "Maurus."
--Mo: "Mo" is the short form of "Maurice."
--French: The original fairy tale is French, and the Disney movie Beauty and the Beast is set in France, so his surname is a fairly obvious reference.

Now onto the characters who exist only in the real world:

Character: Emma Swan
-"Emma" (which also happens to be my name :D) is a Germanic name meaning "whole" or "universal." Hmmm... might this have to do with the fact that Emma is destined to be the one who breaks the curse and makes the fairy tale characters and world "whole" again? Or, as she was born in the fairy tale world but has lived in the real world all her life, she is sort of "universal" because she belongs to both worlds?
-"Swan" is a name and surname after the bird of the same name. The word "swan" is an Old English one, derived from the Indo-European root "swen" (meaning "to sound, to sing"). The writers may have picked the surname just because it sounds pretty, but they also may have wanted to compare Emma with the lovely, elegant creature of her surname, although anyone who's ever met a swan knows they can also be raging assholes, and from what we've seen of Emma, she definitely has her ass-kicking side. Fanpopper tricks also pointed out that there is a fairy tale called "The Six Swans," in which a young woman has to save her brothers from a witch's curse, just as Emma has to save the people of Storybrooke from the Queen's curse. Thanks, tricks!

Character: Henry Mills
-Henry: From the Germanic name "Heimirich," meaning "home ruler." Possibly because he's the only one in Storybrooke who knows what's really going on, or because he's royalty?
-Mills: See "Regina Mills."

Character: Alexandra
Meaning: "Alexandra" is the feminine form of the name "Alexander," which is the Latinized form of the Greek name "Alexandros," meaning "defending men." In Greek mythology, the name "Alexandra" was also an epithet for the goddess Hera, and was an alternate form of the name "Cassandra."

Characters who existed solely in the fairy tale world:

Character: Leopold
-Meaning: "Leopold" is a German name derived from the words leud ("people") and bald ("bald"). It was a common name among German royalty, so it is a fitting name for a bald king!

Character: Gaston
-Meaning: Named after Belle's suitor in Disney's Beauty and the Beast, "Gaston" is a French name, probably derived from either the Germanic element gasti, meaning "stranger," or the Gascony region of France.