I hate to say this but the boards people have widened the gap with the resources out there. As USF mentioned, Kaplan needs to improve R&D because the questions are not the same. This is like the old prey-predator graph from introductory biology. The prey (board type questions) are more sophisticated then the current available questions.
Here is my theory. The test committee (Basic Science faculty at medical schools) meets once a year, March-April,
http://www.nbme.org/AnnualReport/2004/governance.htm. They get together and put in a batch of new questions every year, and retire old questions. Therefore, in 4-5 years majoritiy of the questions would have been replaced with new questions (complete turnover of the test bank). This is one reason that HLA types, and chromosome numbers of disease are showing up less and less on Step 1 exams. HLA subtypes and chromosome numbers were emphasized in the late 90's and early 2000. Also, the UCV series is not as relevant either because the buzzwords are replaced with physical diagnosis and description of the diseases.
As for Goljan, I think Goljan is gold for the NBME shelf exams because they are retired questions. However, the audio that is circulating is from 2002. Sure, I remember many questions that jumped out during shelf exams. However, the test committe has met in 2002, 2003, 2004, and 2005. That is four years of adding new test questions. Granted, you will see goljan's questions, but it won't be as many as you think. The number of questions that Goljan mentions as "you will see this on the boards" decreases year by year because of the influx of new questions. If you see 20 questions verbatim from Goljan's lecture consider yourself very lucky.
Here is my conclusion. If you want to just pass Step 1, then First Aid and Qbank will be enough. However, if you want the 240+ you will have had to already worked very hard the 1st 2 years of medical school. The test is designed so you won't be able to learn new information during your review period. This is why you will often hear people say, "There were questions that I could not have prepared for on the exam."
Also, working hard in medical school doesn't necessarily mean that you have a high class rank. I know some students that have honored medical school classes because they memorized class notes verbatim. Yet, when I talk to them they can't integrate information from one class to another. For example, if I tell them Graft Versus Host disease is localized in the terminal ileum. what type of pathology would you expect? These people can't reason out the pathology because they memorized GI diseases (in their mind they think what are the DDX at terminal ileum) rather than reason the pathology by going backwards (if terminal ileum is affected well the normal physiology is this so if this is knocked out this happens i.e. pathophysiology).
These same people memorize First Aid, BRS Physio, and BRS Pathology verbatim but then during the test realize that Boards require you to think and apply (unlike medical school exams) so they are screwed during the exam. You can pinpoint these people in your medical school because they will say "I wish I did more questions." This is why you will see some students that score below a 240 on Step 1 with a high class rank. On the other hand, there are some students that have learned the material in medical school but have only honored a couple classes here and there, but when you talk to these people they have integrated the information.
Lastly, there are only about 2-3 people out of 100 medical students that have the strong work ethic (Junior AOA) and intelligence (260+ Step 1). These people are truly gifted.
Still, half of these people lack the social skills/personality that are exposed during residency interviews. So I would say 1 out of 100 medical students are truly gifted i.e. have the social skills/personality, impeccable work ethic (Junior AOA), and intelligence (260+ Step 1).
http://www.nbme.org/examiners/FallWinter2001/ForStudents.htm