Matt Zoller Seitz, on No Country For Old Men:

Though they are habitually described as snotty formalists with nothing on their minds but cinematic gamesmanship, the Coens' body of work is one of the most sneakily moralistic in recent American cinema.

This is very smart, and very true. The Coen brothers have made their share of duds, but the people who accuse them of being winking, technically proficient nihilists have it exactly backward, I think. If you don't mind spoilers, read the whole thing.