Just some advice which may or may not apply at your medical school but probably does:
1) "Assigned Readings" in textbooks are usually just wishful thinking on the part of the professor. Your real "meat and potatoes" will be either the course syllabus, on-line lecture notes, or notes from your note-taking service. I'd bet that these will be sufficient to answer 99.9% of all test questions. As to the other 0.1%, you have to ask yourself, "is it worth it." I bet you will barely have time to keep up with all the notes let alone the assigned reading.
2) Avoid like the plague buying a Neuroscience textbook, a full-size Biochemistry Textbook, or a full size Cell-biology textbook. Neuro is so complex that the BRS book or a "High Yield" book will present you with everything you really need and want to know. Likewise, get the cheaper, paper-back Lippincot for Biochemistry because a big book like Leninger is 99% useless trivia.
3) The only text-book you absolutely need for first year is a good anatomical atlas. I have Netters and a Rohan color atlas which has beautiful color photographs of impossibly precise dissections which almost (but not quite) makes going to anatomy lab superfluous.
4) For second year, a good physiology textbook like Guyton would not be too much of an extravegance. I used mine a lot to clarify fine points of physiology. But it is not essential. The "Grid Books" in almost every subject provide more then enough detail to both learn the subject and study for Step 1. I would buy these as required. They are generally a third of the cost of a text book, are lighter, and eliminate the stuff that is only of academic interest.
5) Get out of your head the notion that you have to learn everything. You will drive yourself crazy. Relax. If you learn enough to comfortably pass the test and understand the big concepts you will do all right.
6) Avoid buying a "Textbook of Medicine" like Cecils or Harrisons, even if they say you need it. I paid $140 for mine and have never used it. First of all, they have numerous copies in your library. Second, you can probably get it online at your school's library. Third, you can get it for your PDA for half that price. And fourth, it is just too ****ing dense. Just jam-packed with information when all you really want is what's in "Five Minute Clinical Consult."
Do I sound cynical? I am. Nobody told me these things, or I didn't believe them and so I have about 90 pounds and $1300 worth of books that I never use.
Save your money