I used crush the boards step 3, first aid step 3, and the kaplan qbank question book. Possibly the easiest step exam out of the 3 in my opinion.
Like someone else mentioned, First Aid for Step 3 was the most useful for the clinical scenarios they have included. Plus, download the program from usmle.org or go through the CD that came with your registration to learn how the CCS program works -- that's probably *the* most important part for day 2 of the test.
I agree about Strong Medicine having too many errors -- but it was still useful to hammer some quick facts in the peds and ob/gyn stuff that I had long forgotten as a medicine resident. B&W is probably too detailed for step 3 I think.
The Qbank questions were probably most in line with how difficult the questions are on the real thing. I think I also peeked through a question book by NMS, and those questions were WAY too in depth and detailed.