Hey golfpro, based on the fact that you failed before, I would be a little more excessive. How do you feel about your grasp of the material? If you feel it is decent, then try Qbank and UW (seriously, this sounds ridiculous, I know). Get through all of the questions and understand why you got each incorrect answer wrong. This will help to solidify things.
If you don't feel that you have a mediocre (average) grasp of the information, you should consider really hitting the books and in particular your weak points (ob?, peds?, surg?)...
NBME exams are really good, not for predicting your score like a lot of people use it for, but for identifying which particular areas you are weak in and what you need to study really hard for. This is exactly what I used them for and it kind of paid off.