While I don't like every movie by the Coen brothers, I am a pretty big fan, and I thought No Country was the best movie of the decade. I had to hesitate though before finally deciding to recommend Burn After Reading. See it if you liked Fargo, otherwise maybe not.
A line by George Clooney's character about being a baby is what the movie, and maybe the Coens, think about all of humanity. Their visual depiction of humanity is the expression on Brad Pitt's face when he and Clooney finally meet (watch for it though, you get to see it only briefly).
Acting was fantastic, especially Pitt, and may be another reason to see the movie. This is dark comedy with far more emphasis on dark than on comedy, though. Enjoy!
(BTW, comments are welcome as usual, but please warn if you post any spoilers.)