From three of my favorite movies. Pretty much the order in which I thought of them.
"Give me a scotch. I'm starving." - Tony Stark (Robert Downey Jr.) in Iron Man
It's just Stark's character up and down ...and Downey delivers it so well, I never thought I would really like Stark, but he was played so well I think I'd easily go for a roll in the hay.
"She's starting to damage my calm." - Jayne Cobb (Adam Baldwin) in Serenity
"I am a leaf on the wind - watch how I soar. " - Hoban 'Wash' Washburn (Alan Tudyk) also Serenity
Both of these from Serenity but for different reasons. The first because Jayne's character is just plan hilarious and makes me think about the humor in the thing as a whole, or at least the situations they get themselves stuck in. The second because it makes me think of just how epic the film is as a whole. The whole combination of the genres of sci-fi, horror and western is crazy good and no one could do what Joss did with that idea. Damn fox for killing the series but yay for the movie.
"I'm a dog chasing cars. I wouldn't know what to do if I caught one!" The Joker (Heath Ledger) Dark Knight
It sums up The Joker in a way that is just the real-world version that fractures the slapstick, Hammel-voiced cartoons I remember from my youth. Ledger did such a fantastic job. He is missed.