Second this. I saw it in the theatre knowing nothing about it, am so glad I did. For one thing, the sound is fantastic -- it is perhaps the only movie I've ever seen where I noticed how great the sound was during the movie, how much it reinforced the sense of being present in the reality presented on the screen (I realize there is a bit of contradiction in saying that :).

A few years ago I noticed that I think about this movie that I randomly saw in 2006 (or whatever year it came out) at least once a week, if not more. Some real staying power.