Master and Commander narrowly sneaks in under the 2003 barrier.
Before the Devil Knows You're Dead from 2007. I'd only vaguely heard about this one, so once I'd randomly checked it out my first thought was this: If this movie were released in the 1970's, it'd probably be regarded as one of the greatest films ever made. Story, tension, characters, direction, performances, absolutely a perfect movie.
The problem with "great films" of recent years is that only the blockbuster franchises are getting huge exposure. Casual filmgoers will remember the past decade for Harry Potter, Twilight, Transformers, Bourne, Pirates of the Carribean, etc. There are plenty of great movies if you dig deep enough, just don't expect to be able to discuss them with your coworkers at the water cooler.
+1. this is very interesting.