I don't really like most product tie-in books -- I have to admit that DD brought one "Disney Princess Treasury" book home from school with novel-length retellings of Disney movies, and it was almost shockingly well-written, considering. But generally, they're just total crap.
As far as actual books, we checked out one picture book from the library, The Pirate's Parrot, that was just disturbing and bizarre. The pirate captain's parrot dies so the crew ties a teddy bear onto his shoulder as a replacement, and it ends up being weirdly violent. I was glad when that one was due!