My all-time favorite movie is The Godfather with Marlon Brando. Yes, crime and drama movies are my weakness.
I also like Groundhog Day, Casino Royale, The Devil's Advocate, Ghost Rider, The Dark Knight ( special thanks to my dear Sierra a.k.a Jokers, for introducing this movie to me and The Joker, the most badass villain of all time also), The Mask, Ace Ventura movies and How the Grinch Stole Christmas.
"The Rocky Horror Picture Show" is definitely my favorite. I've never seen anything so perfectly bizarre, and the songs are incredibly catchy. Though it is awkward to go around singing about transvestites and touching people under my breath...
I also like "The Princess Bride" (Inconceivable!), Tim Burton's "Alice in Wonderland", and "Much Ado About Nothing" (because I love both Shakespeare and Kenneth Branagh).