Add one more name to the list. Just registered here and I wish I had found this place months ago.
Currently I have all of the practice tests ETS has released along with a few partial tests from "unknown students". I also have the REA book and its 5 tests. I am under the impression that the best way to study for this test is to complete as many sample questions as possible. That is how our teacher prepped us for the BC Calc exam and I walked away from that test KNOWING that I earned a 5/5. I also plan to go over as much of MIT's "Street Fighting Math" as possible as I have heard that is applies to the GRE very readily.
I took the test once before (4 years ago), and did awful, thus derailing my PhD goals. In the meantime I have gained some work experience and a masters degree so hopefully I will be able to do much better. October 9th is coming up quick and I am thinking that I may opt to additionally register for the November test.
I used The Princeton Review's Cracking the GRE Math Subject Test (4 ed) to review the math, and now I've been working on bunch of problems from the old exams. I'm also using a bunch of textbooks that I used in my math classes as references.