The Da Vinci Code. I was really disappointed in the movie :( There are a lot of differences between the book and the movie, and certain parts weren't in the book at all. Luckily it had been quite a while since I read the book when I saw the movie so I didn't remember all the details, but my sister just read it a month before and she was obsessing over all the differences.

I think there's one big flaw in this movie; those who read the book will get annoyed with all the "errors", and for those who didn't read it I would imagine some parts are more or less confusing or seem pointless. But that's just my opinion ;)