Another Stupid Dragon Question

After the dragon/dinosaur issue from the new Scooby Doo DVD, we watched Rankin/Bass animated Hobbit. My stepdaughter asked about Smaug (if he looked that way in the book) and somehow we started talking about dragon books. She has the new Dragonology book and has read The Hobbit and Harry Potter.

Two questions: What would be your nomination for best dragon book overall? And what would be a good book for 12-year old girls? (She hasn't read Conan and I'm kinda happy to keep it that way. I was thinking the Dragon Riders series which I personally didn't like but has a strong female following.)