I would agree with allyz, in the sense that this question is hard to answer and depends on a variety of factors, including: your baseline level od preparation, how much time you have, how high you're looking to score, which kinds of books works for you and which don't, where your strengths/weakness are, etc.
For questions UW is the most highly-recommended source, at least on these forums.
For text, I am happy with First Aid. I'm not too familiar with B&W, though I did think Crish and Secrets were severely lacking in detail and were not enough!
If you go through all the UW questions and explanations as well as one source of text (be it FA or B/W), you should be fine. I would recommend taking at least one NBME mini test roughly 2 weeks before your test date, to gauge where you stand!