Why, are you going to go out and buy them or something? That's pretty ambitious to start your reading for med school this early. ;-)
Ok, so seriously, these are the books we used for the first block (summer), which covers molecular/cell biology, biochemistry, and genetics:
For molecular and cell biology, we used Molecular Cell Biology 5th ed. by Lodish, et al. This was the book we used the most this whole summer, and I thought it was a pretty decent book. It has nice figures and it's fairly readable. You would definitely need this book for the summer block. Even though we have online access to it through the library here, it isn't complete access. I don't know how they picked which sections to let us read on line, but it's really annoying that we don't have access to large portions of it.
For biochemistry, we are using Textbook of Biochemistry with Clinical Correlations, 6th ed. by Devlin, which I already told you about. This is a pretty dense book, and I have to read it in small spurts with a lot of breaks. I really like the clinical correlations in there though. Basically they give these little blurbs about what happens when this or that enzyme is mutated, and it helps you relate all of this biochemistry to various diseases. That makes it more interesting to learn about things like lipid metabolism that might otherwise seem pretty dry. My biggest criticism of Devlin is that the pictures aren't very good. That's part of why so many of us are also using Lippincott's Illustrated Reviews: Biochemistry. The Lippincott's book has great pictures, but it isn't nearly as detailed as the Devlin book, so you really need to read both. The other annoying thing about the Devlin book is that there are a ton of typos. Someone seriously needs to proofread it before the seventh edition comes out.
For genetics, we are using Thompson and Thompson’s Genetics in Medicine, 6th ed, revised re-print, by Nussbaum. I actually like this book a lot. It's basically a medical genetics book, and again, that makes learning about some of these topics a lot more interesting. We only were assigned three chapters out of this book for two seminars, though, so a lot of people didn't buy it. But I think it's worth buying, and it's short enough (400 pages) and easy enough to read that you could finish the whole thing. There is a bonus section with 31 different diseases that tells you all about the clinical presentations of various genetic disorders.
I haven't finished buying all of the books for next block yet, so I'll tell you about those another time. But I recommend in addition to buying these books that you consider also buying a copy of First Aid for the USMLE Step 1. You might be thinking, why buy a board review book now when you won't be taking the Boards until after your second year? But, it's really helpful to go through the First Aid book while you are learning your organ systems. As you finish each subject, read the corresponding section in First Aid and annotate it. So for example, over the summer, you can read the biochem and molecular bio section of First Aid while you are covering those subjects in school. As you go through each organ block (cardiovascular, respiratory, and so on), read the corresponding sections in First Aid. A new version of First Aid is put out every year around January. I got the 2006 version, which is the first one that has the sections organized by organs. It's ok if you get a used version that is older, but if you can get a version from 2006 or newer, it will follow our curriculum better since we go by organ blocks.