I agree with daelroy...bio, physics, chem, and their verbal reasoning is useful, but not the ochem book. I have the 1001 series for bio, physics, and chem and although they are pretty good, if you don't have enough money, just get the review books. Try and stick to the full-length exams from AAMC and if you can a hold of the TPR, Kaplan, and Berkeley exams-perfect. Check on ebay because you might be able to get these exams at a more than reasonable price.
Oh, and to answer your question about which book to get if you're taking the Kaplan course...it really depends how strong/weak you are in the sciences/verbal. I took the Kaplan class too and still found the EK series more than useful. I took notes on all the Kaplan books, EK books, and did half the 1001 books. Kaplan has a great library of practice tests (discretes, sections, FL, topicals)-do these. If you don't have enough time, make sure you do all of their FL's and topicals. I thought that Kaplan's review books were pretty decent (some parts were confusing), but the EK series definitely helped clarify murky concepts and provided another perspective on re-learning this stuff.
Bottom line, if you have the time and money to get the EK books, then I would suggest you get them. They helped a lot for me, but other people may disagree.
PRACTICE, PRACTICE, PRACTICE.
Good luck!