All of those books are probably overkill for step 2. I agree with jeebus that you really don't need more than one. A single comprehensive review book is good enough.
To be honest, your highest yield for boosting you score in step 2 is probably going to come from doing questions. If you really think about it, the clinical knowledge of a third or fourth year medical student is fairly limited, and they test appropriately (unlike step 1, when any basic science principle is fair game). For the most part, you aren't going to get a lot of "one-in-a-million" questions. They tend to stick to the bread-and-butter stuff that they want to make sure a medical student has a grasp on. Therefore, there are only so many questions they can ask, which makes doing oodles and oodles of them prior to the test important. Once you've seen enough of them, it's hard for them to surprise you with anything.
