The only books I used for Step 1 was First Aid, the Kaplan Lecture Books (didn't go to lecture, bought them off a student the year above me), pharm cards (pharm sucks at my school), and then tons of questions in Q-bank. I didn't use any extra books, especially none for molecular crap (I hate that stuff). No BRS books or anything like that.
I studied probably 5 weeks, about 8 hours per day. I always ended with doing 2 hours of Q-bank questions every night. I would recommend doing all subjects randomally not just what you read that day. This way you are always reviewing everything.
I thought First Aid was invaluable. After reading a section in Kaplan, I would read the corresponding section in First Aid. I actually read though first aid 3 times: once at the begining in early may, after each section I read in kaplan, and then in the last week before the test. I feel that First Aid and Q-bank were both awesome.
So I only used four sources and was completely happy with my score. I think using all those supplemental sources is not needed assuming you learned the material well your first two years of med school and just need a review.