I used Hall and McGraw-Hill review books which are very detailed. McGraw Hill is not the same type of question you will see on the exam but has a lot of questions testing basic and complex facts. The ACE questions are very helpful but IMO are slightly easier than what you should expect on the real exam. I also used Big Blue which I found helpful when you don't have time to read an entire textbook - it's in an outline format, with all the fat trimmed out and the facts that you need to know are in there.
Hope this is helpful.
I took my boards this past August and I'm selling all my books - if you're interested, PM me.