I actually think that applying to 30 programs IS too many. I applied to 29 and regretted it, as I got invited to 22 interviews and ended up cancelling 10 of them. That's a lot of extra money, as well as administrative time to manage your schedule, email coordinators to cancel, and so on.
I chose 4 geographic areas I wanted to focus on (Boston, New York, Philadelphia, California), applied to programs in each of these areas, and then arbitrarily added a few other programs that simply interested me (Yale, Duke, UNC, Dartmouth, JHU). I referred to the FAQ on this board which points to
http://forums.studentdoctor.net/showthread.php?t=48717 as a sample list of "top programs" and found that about half of mine were on the list, the other half were "local" programs that I threw in just because they were in my three geographic locations.
The breakdown is that I got invited to interview at 5/6 Massachusetts programs (didn't hear from B&W but got all others), 7/7 NYC programs, 3/4 Philadelphia programs (didn't hear from Drexel, which was a "local" program), and 2/3 California programs (no from Stanford), plus 4 more programs that weren't in any of those areas. WAY TOO MANY TO HANDLE. I cancelled all of my Philly interviews except for UPenn, half of my NYC interviews, and all the California interviews.
End result is I interviewed at 12 residency programs (8 were on the "great programs" list I linked to above, 4 were not), ranked 8, and matched at my favorite program (which I had dumbly listed at #2 on my list but am really glad I didn't get #1). If I were to do it again knowing how pleasantly surprised I'd be at the number of interviews you really can get as an applicant, I'd trim my applications down to 20 programs knowing which "local" programs really wouldn't suit me.
Also, one thing worth noting is that at some of the "local" programs where I interviewed, the population of other students being interviewed was totally different from my background -- number of international and foreign medical graduates and other applicants with significant hurdles to overcome was >50%. I did not start seeing a majority of students from a similar background to mine (average grades, good boards, average allo school) until I reached Yale. Bottom line is that YOU REALLY WILL INTERVIEW AT STRONG ACADEMIC PROGRAMS if that's what you want, and there are some small programs in the middle of nowhere that you probably won't need to spend time interviewing at just to find that you have no desire to rank them.
Anyway, since before going into applying you don't know exactly what you want, it's probably tempting to apply to 30 programs.... but I think if you can choose what you want (say, choose "only" the better known programs or those with the bigger names -- which with your grades should be definitely fine for you) and pare the list down to 20, you'd have few regrets. Take yourself out to dinner with the extra money.