I just re-read this book (February 2013), this time reading it to my seven year old. It's just better with kiddos! She loves it. The movie is also better through a kid's eyes.
I didn't give her any spoilers, and she fully expected Snape to be an agent of Voldemort. As she would think, since the main characters think so too!
Also she thinks that Harry and Hermione might develop a romantic relationship. That's the kind of thing you think when you read 'em for the first time! :)