Well I don't quite know about a crush, but I do worship J.K. Rowling. Why? It's not so much her writing talent as it is her ability to a) create awesome characters, b) think up intricate plot lines, and most importantly c) research, research, research, which I never, ever manage to get the motivation up to do. And it makes me squee.
... okay, so maybe I would fancy a bit of a grope. *cough mutter blush bolt*