Tell It To Me Tuesday: "Here's Looking At You, Kid"

There are classic movies. But better yet, there are classic lines from classic movies. What is your most favoritest classic movie line ever uttered and why?

P.S.- By request, my favorite movie line is probably one from Can't Buy Me Love:
"Cools, nerds, your side, my side...man it's all bullshit. It's just tough enough to be yourself."