Note, this is for your studying 4 to 6 weeks prior to the Exam when you are doing nothing but studying:
The 2 best resources are: 1) First Aid and 2) questions. Hands down. No questions about it. In fact, that's almost all that I felt like I had time for. I would really recommend making First Aid the bulk of your studying, and make sure to supplement it with lots and lots of questions from either USMLERx or USMLE World or better yet, both. For example, I would really recommend shooting to do at least 2,000 to 3,000 questions total (including questions from practice exams though). And if you can do more, that's even better.Really truly. Everyone really totes USMLE World as being the best (which it very well might be), but a classmate who killed step 1 recently told me that he feels like USMLERx probably got him more points on Step 1, which in looking back, I think might be true for me too. (But I'm not sure because I did more World questions.) USMLE World is more expensive, so most often people only get it just the month prior to their exam.But RX is cheap enough that you can get it for a longer period of time if you want.
I also liked the simulated exams that World had too, and I did both of those as some of my practice tests (see below for more). And I felt like the NBME tests were worth buying at $40 a pop. Also, Rx allows you to create practice tests using their questions.
During each session, I would just study one subject. I made sure that I always studied First Aid for a given subject first, and then I would spend some of my session time doing questions in that subject (although, some of my classmates advocate that when doing questions you should always do just random questions from all subjects all the time...) or studying that subject from another book if I felt like I had already covered everything in first aid sufficiently. The only book I would recommend supplementing First Aid with is Goljan's rapid review book. It is a pretty good book. Additionally, it might be worth setting aside a few sessions to cover topics in Goljans book not covered in the list that the Columbia guy gave us. For example, I thought it was really worthwhile to review the vitamins and some of the early chapters in nutrition stuff all on their own. Also, listening to the Goljan audio while I ran during lunch was really helpful too. Others I know liked to listen to it at home at the end of the day as a way to wind down instead. But all in all, Goljan just has a good way of putting things together.
However, the exceptions to this (for me) were: Behavioral Science, Pharmacology, and Embryology. For behavioral science, BRS behavioral science is a gold mine. I highly recommend going through all of this book. I also feel like the last half of the book is more valuable than the first if you have to pick and choose what to study. A lot of easy points are missed in Behavioral Science. For pharmacology, I also used BRS pharm cards. I didn't even come close to getting through all of them, but I like flash cards for pharm (although First Aid really is sufficient). And for Embryology, I skimmed quickly Hi-Yield embryo.
But once again, all these other books are merely supplements to first aid and questions, and if you have to choose studying one thing over another, CHOOSE FIRST AID AND QUESTIONS FROM Rx OR WORLD! I had a friend that tried doing some of the other BRS books at first (like physiology and pathology and what not), but he really felt like that that did not help him and he wishes that he would have just done first aid more. I also tried using "Step Up to the Boards", but I think maybe I should have used that time to do more questions...
For those wanting to start studying long before the test:
Supplement your studying for classes with USMLERx questions and feel free to use other step 1 books such as the BRS series. But depending on your medical schools reputation for how well the classes prepare you for step 1 and especially if your classes are graded vs pass / fail, make sure you do well in those first and foremost.