I don't know which is the best, but I used the REA book. The "frequently used vocabulary" section was quite helpful. There were only a handful of words on the actual test with which I was not familiar.
Most decent guides should help you brush up on your math, which is generally the easier section to boost your score. After all, you learned most of it in high school already.
I got a 650 verbal and 760 quantitative on the old test. I'm not sure how the new test is, but I heard the verbal section got easier and the quantitative requires more calculations. Good luck!