According to a news story, The American Library Association has placed Twilight, the series of teenage romance books vampires and werewolves by Stephanie Meyers, on list of the Top Ten Most Frequently Challenged Books of 2009.
This is a list of books that people are said to frequently find offensive.
I've never read any of the books in the Twilight series - primarily because I thought that, as books aimed at teenage readers, they'd probably be too inoffensive.
I guess some people are easily shocked.
Links to news stories on the subject: