i've been wondering about this myself...i've been out of school for a few years, and imagine that any letter i could get from a humanities prof, at this point, would be of the "well, i gave her an A on her paper and she seems great but i barely remember her" variety. is it better to have a positive but fairly generic letter from a non-science prof, or none at all? (i have 2 very strong letters from volunteer & non-lab work supervisors.)