If you're a first year student wanting to get ahead, I'd invest in some of the BRS (Board Review Series) review books--especially Chung's Gross Anatomy, Costanzo's Physiology (1st yr), and Schneider's Pathology (2nd yr). They are pretty in-depth reviews that are great for class test review, in addition to solidifying what's really important to know.
The benefit of this is that you'll already be very familiar with the books by the time to come to the boards, and your review will be more in depth than First Aid (First Aid is a great book, but I'd concur with other posters and say that it's not enough for a great score).