I agree with everyone's recommendation of "Dark City" -- a very dark SF/fantasy flick. Didn't know what to expect, but was pleasantly surprised.

For mind warping entertaining: "Memento" (Guy Pearce, Carrie-Anne Moss, Joe Pantoliano) and considering this is Daily Kos I can't believe no one suggested "The Manchurian Candidate" (1962 version-- I'll never be able to look at Angela Lansbury the same way again).

Other political flicks-- Also second the recommendation of "Primary Colors", Travolta was awesome. Also "Bullworth" with Warren Beatty and the always lovely Halle Berry (kind of over-the-top, but reportedly one of Howard Dean's favorite movies, you'll know why when you see it) and "Bob Roberts" (Tim Robbins).

Oh yeah, "Wag the Dog" :)