Hey I just finished and got a 670 (first practice test was a 530 but I moved up quickly from there.)
You should do these books in the following order:
1) Princeton 2004 - Hands down THE best guide for test-taking strategy and how to get inside the testmaker's heads. This guide will help you get the right answer on questions where you don't have a clue. Its not about making you smarter...its about making you do well on the test. Beware though, the practice problems/tests are overly simplistic.
2) Next you're going to want to do Kaplan 2004, with or without CD-ROM (personally I think their software sucks...this is bschool and its designed like some PBS kiddie sh*t.) Don't spend much time going over their strategy...Princeton did a better job of this. Get into the meat of the practice problems and the practice test. These are some of the hardest problems, so you're going to want to sweat it out here.
3) Within 2 weeks of your actual test, the last book you need is the 'Official Guide to GMAT 10th ed." which is published by ETS and contains actual GMAT questions. These are the same questions you'll be seeing on the actual exam, some even with the same numbers! Spend a week or so going through the practice problems for each section (over 250 problems per section!) Its mixed difficulty but it seems to have harder questions around the 150 range or so. In the 2nd week you'll want to take the two ETS practice exams for download of their website (free.) This is almost a dead-on predictor of your score.
4) A few days before the exam, go to the gmat.com site and take a look at the choice of essay topics. These are all ACTUAL ESSAY QUESTIONS that will show up on the exam. Sure the essays don't figure into your score, but admissions will still read them. Why not be prepared? Prepare a brief outline for each essay topic. This way you can finish your essays quicker and use some break time to gear up for quant.