Tom beat me to it, and then everyone else beat me to it, but The Man Who Wasn't There is one of the best movies. And the entire movie, like, is just a showcase for Billy Bob Thornton's voice.
What is weirder is that you can listen to the commentary track on that DVD, and he has as many smart things to say as either one of the Coen brothers. Even the monster magazine story is funny. For someone that good to be that awful, it makes me suspicious. I wonder how his life works.