Another vote for 2001. Heck, lets go through AFI's top 25 movies that I watched with some friends:
24. Raging Bull
23. The Maltese Falcon
22. 2001: A Space Odyssey
8. On the Waterfront
5. Lawrence of Arabia
2. Casablanca
1. Citizen Kane
Raging Bull and On the Waterfront, seriously, two boxing movies? I'll admit that Maltese Falcon, Casablanca, Lawrence, and Kane are "classics", but it doesn't help them from being boring. I enjoyed the Grapes of Wrath for some reason, can't recall why.