Recommended test prep books for GRE?

I didn't really use books. The problem I have with books for studying for the GRE is that they don't really give you enough problems to work. I'd try signing up for a class if you have the time and money. Having a class gave me access to tons of math problems and reading passages. But if you want to use a book, I would go with Princeton Review.

GRE classes is nice, but they cost money (and college students ain't made of money =P). I would preferably study on my own. But I will consider taking one if the need ever arises.

Got any other recommended books besides Princeton Review?