Saw The Manchurian Candidate some days ago, and never found the time to mention it. It's a pretty good update on the classic political thriller, and as David points out, Meryl Streep--whom I've never been a fan of--is excellent in it, mainly because (I think) 1) she's a villainess here; and 2) it's a comedy (a very black comedy at that) that 3) requires intelligence, of which she has plenty.
I'd say the fundamental difference between this and Frankenheimer's classic (other than the updating of setting and references) is the shift in emphasis from the Raymond Shaw character to the Captain Marco character. Laurence Harvey's Shaw was the tragicomic heart of the original Manchurian, I think; it went so deep into his skin and his relationship with various people (not to mention his mother) that you mourned the loss of his humanity, the same time you laughed at his irascibility (maybe you mourned him because he was so unlikable, so recognizably human).
This updated Manchurian focused on Denzel Washington's Captain Marco, on how he deals with his nightmares and suspicions and how he makes himself heard. Washington makes the most of Marco, a frightened lab mouse of a man; Liev Schrieber's Shaw in comparison is essentially a distanced concept that shows intriguing glimpses of soul.
Final note: the brainwashing scene is nicely nightmarish, but not insane, the way the original was. Wish Demme came up with an equally nutty if not nuttier sequence (I mean, he's a Corman alumnus, dammit). Not Demme's best, but possibly his best in a long time.