I have taught three graduate level courses during my first graduate program (an MSPH in Epidemiology) and am planning for apps to MD/PhD next year. I really think a valuable letter for me would be from a student that I have taught for three semesters (in addition to including my TA Eval reports, and getting letters from each of the professors I worked for).
However, that said...I have worked over a year in 5 different research labs (with about a handful of publications), have three different degrees (BS Biochemistry, BA Anthropology, MSPH Epidemiology) and work in a clinic. I have a lot of experience and therefore a lot of letters.
I can get letters from all these people, but what is the upward bound likely to be on letters of Rec? Too many seems excessive, but I tend to think diversity is more important that getting a letter from all of my laboratory PIs, and all of the professors I have worked for (both in science and in humanities). If I do this I have 10 letters right there (from professors), with out considering letters from my clinical supervisors, students, or the directors of programs I volunteer with....
Though this might not seem a dilema...its giving me some stress as I start putting together my letter file for next year. How many letters is "standard", how many letters is excessive...and how many letters will make admin commitees think I am a snotty little brat tooting her own horn? Any suggestions welcome. Thanks