Ocean's Eleven

Effortlessly cool. This movie established Brad Pitt and George Clooney as worthy successors to Paul Newman and Robert Redford before them. Soderbergh's fingerprints are all over this one, ensuring editing and cinematography never give you a moment to overthink, but always gives you just enough to guess what comes next.
Stellar ensemble, excellent performances, killer soundtrack, and a defining entry for this kind of story.