AMEN TO SHAWSHANK.
I also have to recommend highly ANYTHING by Akira Kurosawa (Rashomon, Yume (Dreams) Akahigae (Red Beard) Ran, Ikiru are my favorites).
If you're looking for something more contemporary, try the Departed, Angels in America, The Prestige, Children of Men, Twelve Monkeys, Brazil, Fisher King, The Big Lebowski, Fight Club and Malcolm X. that's part of the long list (and it is indeed a long list)

Those who challenge me that Kurosawa is not a god is wrong :-P