I found Barron’s Military Flight Aptitude Tests (By Terry Duran) especially useful while preparing for the aviation portions of the test. There was some review of the general knowledge sections of the AFOQT, but supplemental materials were definitely necessary. I would recommend GRE study materials for your verbal and quantitative review.
As for the study guide, I think AFOQTGuide.com is top notch (my opinion may be slightly biased) when in comes to AFOQT prep.
What do you think? Which book/study guide worked best for you?