Avatar: Highly recommended. Besides the superlative visuals (we saw it in 3D, albeit not IMAX), the story and characters are well-crafted. The political message is formulaic and at times heavy-handed (as when the colonel says we have to preemptively fight terror with terror, or some such) but not to the point where it significantly detracts from an absorbing experience.
Keith Cowing has been pressing NASA to use the film for outreach, which doesn't seem like a bad idea.
UPDATE 1/26: David Boaz sees the film as a defense of property rights.
UPDATE 1/28: An astute observer asks me why, given that the unobtainium is underground, the company couldn't use such techniques as horizontal drilling to obtain it without destroying the Navi habitat.