We saw The Girl with the Dragon Tattoo today and it was FANTASTIC! I mean, don't get me wrong it's dark, eery and there was a part where I thought I might throw up, so you definitely have to be prepared for that but it was great! I thought they did the book justice, which I feel rarely happens when it comes to books made into movies. You should definitely go see it but maybe you should read the book first, just because that's the way it's supposed to be, right? I give the movie an A+.
Here's my review of the book. I think seeing the movie made me want to move on with the next book.