I'd buy Princeton Review and Barrons. Princeton Review is easy to read and has a great format. It's good for reviewing and clarifying the concepts. And the Princeton Review practice tests are probably the best indicators of how you'll do on the actual test. Barron's is good because it has some content that is lacking in Princeton Review. Some people think that Barron's actually gives excess information, but I think it is still helpful. The best way to review is just to take as many practice tests as possible.