Best movie? Who can pick a single favorite? But I'll list some of my favorites:
Happy Gilmore
Tommy Boy
As Good As It Gets
Austin Powers 2: The Spy Who Shagged Me
Bill & Ted's Excellent Adventure
Saving Private Ryan
U-571
Fight Club
Top Gun
Splash (well.. the first 20 minutes are awesome)
I'll consider this a running list. If I think of more, I'll add to it later.