For me, it is probably a three-way tie between Hackers (1995), Super Troopers (2001), and Clerks II (2006). Those movies I watched so many times in the years I was with my husband, I think I could quote all of them somewhere between 80% - 90%.
Some of my faves:
"So what's your interest in Kate Libby? Academic? Purely Sexual?"
Phantom Phreak & Dade Murphy, Hackers
"He thinks I'm Mexican."
"You're not Mexican?"
Ramathorn & Rabbit, Super Troopers
"You swung at me!"
"Because you swung at me!"
Dante Hicks & Randall Graves, Clerks II
You don't have to offer quotes if you don't want! LOL, but I just tend to talk in movie quotes a lot of the time, and these three are my favorites. It's always awesome when you meet someone who totally gets the quote, too.