Maestri's book is great, and he's got a sequel out that's also good. My favorite for animation in general is The Animator's Survival Kit, by Richard Williams. It's not for 3D per se, but it's awfully good.

I buy all my new books at Amazon, because it's cheaper. I also get a lot of good books at used book stores. There's a chain around here called Half Price Books; I've gotten some really wonderful books there, on all topics, at really good prices. Plus, they buy old books (it's not a lot, but it's better than giving them away if you don't want them anymore).