Mac Question: What Books Should I Buy?

I’ve owned the Macbook Pro for a little while now, and am getting comfortable with OS X. I think it’s time to dig a little deeper though, so I’m going to buy a book or two.

I’m a long time computer user, and have a lot of *NIX experience, so I’m not looking for something too basic. I’d like something that will teach me the ins and outs of the whole operating system, and let me go from being “comfortable” to “power user”. I’m leaning towards Mac OS X Leopard: The Missing Manual, but I thought I would ask here if anyone else has any other recommendations.