Passed first time
I just sat the NASM exam today and managed to pass first time. I have to say whilst it was difficult, I didn't think it was as hard or as "tricky" as some of the reviews here had suggested.
I just went through the book a chapter at a time, worked through the study guide and watched the dvds. Once I had completed the book I made revision cards with the main glossary terms and tips I'd picked up here - overactive/underactive muscles in squat assessments etc etc.
I think the key is really understanding the concept behind the subject so not just learning it parrot fashion. The questions are worded differently than in the practice test that's for sure - not tricky though if you understand why the answer was right or wrong in the first place.
I did take the practice exam maybe 10 times before the actual exam and also purchased the "pass or your money back" study materials from this site and found them to be very helpful (though many questions were not appropriate for the NASM exam) the majority of questions were very helpful.
Best tip I can give is don't freak out with what you read on here. If you read through the book, do the exercises and know your stuff you will pass. It is a hard exam but not impossible by any means. If it had been any less difficult I think I would have felt robbed!
Good luck to any new test takers!