I've heard many good things about it (and I like Rachel McAdams every time I've seen her so far) but I'm somewhat put off by the horrible one-sheet being used to advertise it.
I know that is a horrible reason for moving a film down the must-see list, but it's visceral. If you haven't seen it, you can at the movies IMDb page (
http://www.imdb.com/title/tt0356680/combined ).