Really?
Wow, I don't think I've heard anyone say that the third book is their favorite of the series. For some reason I just didn't like it, though I really liked the introduction of sirius black, and the night bus, and hogsmed was cool, I just didn't get into the third one as much.
For me my favorite would have to be the fourth book, I really like how she incorporated other schools into it, showing us that there are more "witchcraft and wizardry" schools out there not just hogwarts. Also I thought the triwizard tournament was just amazing.
but thats what I like best about the harry potter series, not everyone likes the same book so when you have a conversation with people there are lots of different views. (i sound like a geek) ha