Here are some quotes, the best ones

Kill Ari Part 1
"Sometimes I used to picture you naked,"
Then Ziva is there, simply watching.
"I'll call you back," said Tony hurriedly as though he was on speaker phone
Then he stutters various gibberish along the lines of "it's not what it looked like"
Thus the very first question Ziva asked Tony was "Having phone sex?"

Tony: You ever Gibbs Slap me again David and I will slap you back harder.
Ziva: I was following orders!

Cover Story
Ziva: It was no secret. He's writing about us!
Tony: Oh come on, it's not about us. I mean the whole part about Liza and her broken heart.
Ziva: The memento she keeps from a relationship that would never have a chance to happen.
Tony: Yeah, where’s he getting than? Or the scene between Liza and Tommy where they pour out their hearts to each other and spill their secrets
Ziva: Haha. When he tries to explain the profound nature of his identity crisis.
Tony: Yeah! I mean the hidden struggle between ‘who he is?’ and ‘what he’s becoming?’ I don't even know what it is.
Ziva: Totally unrealistic.
Tony: Would never happen

Judgement Day Part 2
Tony: Surprised it took you so long. Thank God for Ducky.
Ziva: (looks at the drink) You have not listened to anything I have said.
Tony: Its only been three years, I’m a slow learner.
Ziva: (while she sits down on the table) And a slow healer. You are crying over spilled… milk.
Tony: Its not milk that I spilled.
Ziva: Do not do this, Tony!
Tony: Do not do what? Blow my in protection detail, blow my undercover assignment? (Drinks)
Ziva: Those sound like apologies?
Tony: (Sights and takes another glass from Ducky’s drawer. He puts it on the table and offers a bottle to Ziva)
Ziva: (Takes the bottle silently and pours drank in the glass. Silence.)

Tony: She died alone.
Ziva: We are all alone.
Tony: Yeah, thanks for that. I just mean that she never got married, never had any children. I never even heard her talk about it.
Ziva: (Sights and looks away.)
Tony: Paris... That’s when it must have happened.
Ziva: The two of them (Gibbs & Jenny) alone, in another world…
Tony: Putting their lives in each others hands, every day.
Ziva: Not to mention the long nights…
Tony: It was inevitable.
Ziva: (Looks at him for a moment and then sais) Nothing is inevitable.
Tony: (Keeps looking at her)

Under Covers
Ziva: Think they bought it?
Tony: I did.
Ziva: That’s fairly obvious.
Tony: For your information that’s my knee.
Ziva: Whatever. You can get off me now.
Tony: It’s only been ten minutes. I have a reputation to protect.
Ziva: We're not even sure if we’re under surveillance yet Tony.
Tony: You can’t be too careful when you’re undercover. Let’s give it another forty minutes just to be realistic.

Singled Out
Ziva: (doing stretches) We could be missing something. (bends over)
Tony: (checks out Ziva's behind) Believe me, not from this angle.

Sandblast
Tony: Ziva! Hey! What the hell are you doing?
Ziva: I can disarm it.
Tony: OK... Well, great. Let's go outside and talk about this.
Ziva: If it detonates before EOD gets here, we'll lose evidence.
Tony: Well, what a bummer! That would be a real shame. Ziva! ZIVA! This has to be the stupidest thing any human being has ever done!
Ziva: Then why are you following me Tony?
Tony: I don't frickin' know!
Ziva: Here, hold this.
Tony: Any idea what's going to happen if this cellphone rings?
(Ziva works at disarming the bomb)
Tony: I can see down your shirt right now.
Ziva: I don't think your new girlfriend would like that.
Tony: What are you talking about? I don't know what you're talking about.
Ziva: I'm talking about you and the fact that you no longer stare at every woman when they pass you by.
Tony: Well, I'm looking down your shirt right now.
Ziva: See anything good?
Tony: Yeah. Real good, but I'm not entirely sure it's worth dying...
(Ziva clips the wire)
Tony: ... over.
Ziva: Not worth dying over. (She zips up her jacket). I'll remember that.
Tony: What if I said it was?
Ziva: Now you'll never know.