I'm just gonna list what I haven't seen out of AFI's top 100:
The Grapes of Wrath
The Bridge on the River Kwai
The Treasure of the Sierra Madre
Bonnie and Clyde
It Happened One Night
The Gold Rush
The African Queen
Who's Afraid of Virginia Woolf?
Saving Private Ryan
The Last Picture Show
Do the Right Thing
I also haven't seen The Wild Bunch
, but will be doing so very soon.