I passed all seven exams on my first try and I only used one set of books: David Kent Ballast. I swear by his stuff. I even used the books for the old ARE 3.1, not the newer ones (I did look once through MEEB before the mechanical section. I also used the ARE Forum quite a bit.)

Ballast's books are cheaper and apparently far more reliable than Kaplan. Many people on ARE-Forum report having bad experiences with Kaplan.

ARE Forum

I used old versions of Kaplan and Ballast from 3.1 they were still adequate (construction info has not changed too much over the last few years). You should also get Dorf's book for the Vignettes.
That should be enough to eek by and pass. If you really want to be confident when you walk in... you are going to need MEEB, Architects Handbook Prof Practice and Fundamentals of Building Construction also... Also as farwest mentioned, the AREForum is invaluable for help with questions and vignette critiques.
I passed all on 1st try too, the tests weren't too bad, just make sure you prepare..

MEEB is a fantastic reference for anyone in the profession, and really should be in the library anyway.

It doesn't overcomplicate concepts and gives you a reasonable understanding (although not in too much detail) of how most systems operate.

If you are interested, I can give you some more books that I suggested to architecture students that were involved in my technical courses- they may not be applicable to the ARE, but are a great primer for non-engineers.

Thank you!

I bought the Kaplan and totally regretted it. It's really poorly written - often too vague (and then the practice test questions are on very specific stuff that is covered nowhere in the book), constantly repeating itself (they hired different writers to write each little chapter - and then apparently NEVER edited it for coherence, so a lot of the little chapters just repeat content from other chapters in a slightly varied way), and most importantly, simply doesn't really give you enough information to feel confident on the exams.

I took the 4.0 series and passed them all - but I credit that almost entirely to my experience in the field, which really does come into play on the exams. I did use the Kaplan books (since I owned them and could write in them) as a "first pass" and basically just read them straight through to give me familiarity with what I already felt strong on and didn't need to study more, versus what chunks I really needed to learn more about - and then I went to my local AIA office and spent hours reading the Ballast books (3.1 series) for an in-depth treatment of the areas I was lacking in. Does that make sense?

I never read MEEB (and didn't miss it) but felt strongly that I should have read the Architect's Handbook and didn't.

The one book that I simply do not see how ANYONE can pass any vignette without is Professor Dorf's Solutions book (for the vignettes). Literally all you need to do to pass the vignettes is read his book & follow the advice to the letter. I practiced my vignettes once time each, following his example, and felt 100% confident of every one of them on the exam. His book is a lifesaver.

If you are located near an AIA office, they usually offer the Kaplan guides to borrow for free. I wouldnt waste $ purchasing them. It is a very basic overview of the whole thing, and thats really it I bought the ArchiFlash flashcards, only $100 and they were almost all i used for several of the exams. Well worth it Ballast and MEEB seem to be really good resources as well, especially if you can find cheaper used copies I didnt use the Dorf for my first couple exams, but am now on Structures and Building Systems, so i think i will check out the Dorf stuff. I hear it is really helpful

I wrote a review of every book I used for each test on the ARE. http://www.youngarchitect.com/2014/01/03/the-ultimate-list-of-are-study-material-part-2-each-specific-multiple-choice-exam/ 

I was suggested to take a class to prepare for the exams. Did anyone actually do this?

Get them all!! study them all, all the time....... as if your life depends on it!! because it does. after all, it your livelihood for the next 40yrs so why skimp!!!!!

YES! I took that 38 hour online structures course, it was excellent!!!

I struggled with structures in school, failed the test once and was terrified of retaking that exam. The class was excellent and got me up to speed very quickly. I kicked ass on structures the 2nd time around. 

Not having a good structures foundation before I started studying for structures, Ballast and Kaplan really confused and werent much help.