Don't use the current Kaplan book! Honestly, I never felt so completely downtrodden about the GRE as after I waded through their terrible sample questions a few days before I took the actual test. I scored extremely well on the GRE, but I never did well on any of the Kaplan practice tests. Not a quality product to say the least. The ETS book is much better according to a friend of mine who used both. Definitely check out their online tests if you have a PC or can get access to one. They seriously allayed my nerves after the Kaplan disaster, and taking them will familiarize you with the new computerized version.
Make sure to do some practice essays, even though you won't want to at all. Coming up with appropriate nonsense to answer their questions in the allotted time is harder than it looks.