Where the Wild Things Are
While this is technically a thread for discussing the movie, it's certainly appropriate to discuss the book as well.
If you haven't seen the movie yet, I highly recommend it. It does capitalize on nostalgia a touch (not that I'm opposed to that sort of thing - it just has to be done properly), but it does an excellent job of interpreting an old classic and exploring the themes therein with greater depth and intensity than could be done in a children's book.
Naturally, they had to add a fairly substantial amount of content, since the book itself was so short and contained a very simple plot. The content they added explored many of the themes in the book to a great depth, and did so in a way that is very much aimed at the young to middle-aged adult. In addition to the themes of emotional maturation, exploration, and isolation, the movie explores friendship and relationships in general, particularly addressing changing relationships, drifting apart, and so forth.
Bring tissues. If you're human, you'll likely need them.