My brother-in-law's knocked-up girlfriend's daughter's birthday party was Saturday night. I ended up buying her a boxset of books - "A Little Princess," "The Secret Garden," and "Anne of Green Gables." All books I loved growing up (2 out of 3 are still on my book shelf today) and she loves to read, which is great.
Our gift was the only gift she got besides toys and clothes. I'm a firm believer in the gift of books. Books won't break. You never really outgrow a good book (you just get faster at reading the story). The birthday girl, Zannah, is in second grade, but is an awesome reader. Last year, she was reading chapter books.
And, if she doesn't like the books, I included a gift receipt so she can return for store credit and pick out different books.