Of those in the poll that I've seen:
-I am Legend - A decent movie, great acting by Will Smith. But I really think this movie could have been much better than it was with some better writing.
-Michael Clayton - I easily could have voted for this one. Great suspenseful drama, and a great performance by both Tom Wilkinson and George Clooney. Definitely an underrated movie.
-There Will Be Blood - I went in to this movie with high expectations, and I wasn't dissapointed. Amazing script, and Daniel Day Lewis was at his best. Maybe I'm biased because he's my favorite actor, but one of the best performances I've seen in a long time, if not ever. If this doesn't win best picture, it's a travesty.