My personal opinion is niether one of us should be answering this because niether of us has taken the USMLE's yet. Bigfrank is the guy most informed right now who it would be best to answer this question.
As for my uninformed answer to the OP's question. I've been following this USMLE forum for 3 years now, and whenever anybody takes that test, regardless of what they got, they always say: "I wish I had studied first Aid more"
I was actually at your spot 4 days ago, having finished an in depth review of all everything. What I decided to do is this:
I had the lowest %'s at the time on Q-bank on immuno and Gross, so I went to my med school library, sat down for 6 hours and read high yield gross anatomy and high yield immunology, copying everything into my first aid.
Once I did that, I am just going to reread first Aid as many times as I can and reread BRS Path a few more times (just finished reading #2 of board studying, about #8 in lifetime). It takes me about 1.5 days to read first aid, and one day per BRS path. I'll prolly give up rereading path much more because I'm not missing many of those on Q-bank.
So, moral of the story is: Read first Aid. That's what everybody always says they wish they did more.