Wow, good question. So many great ones. You really can't beat Stanley Kowalski, or Paul in Last Tango, but I love some of the subtler or weirder ones. I think Reflection In A Golden Eye is an incredibly underrated performance - one of the best understated performances I have seen. I also like him in some of his other 60's era oddities, like The Chase and Burn! He is one of those rare actors that make any film watchable - even if the film isn't particularly good, I will watch it just to see what he does. Alot of people hate his portion of Apocalypse Now, but I love his performance there - broken, lost, esoteric, despairing - but always engaging the audience, even when his head is down and in the dark for nearly entire scenes. He is so revolutionary in his choices. Yeah, he is my favorite of all time. How about you? What are some of your favs?