<p>Well, for the AP Spanish exam, my class uses:
1) Barron's 'How to Prepare for the AP Spanish Exam'
2) AP Spanish: Preparing for the Language Examination (my teacher takes the quizzes from this book, and the majority of us fail them... but it's really, really helpful)
3) La lengua que heredamos (this book is completely in Spanish, but it's very, very detailed.. and very helpful)
4) Barron's Let's Review Spanish (Regents Edition) (it's made for the nys regents course, but because a lot of the students in my class are good readers, good speakers, but terrible conjugators, we use this to review tenses) </p>
<p>For AP Calculus AB or BC, Princeton Review is the most concise and useful.
Princeton Review goes well with AP Physics C too, but you might want to supplement PR with Barrons'</p>