This is something we touched on briefly during theory classes up at college. One thing you might want to consider dedicating some time to is the entomylogical (sp?) derrivation of the terms- they refer to size, not tonality or "quality." Specifically, the distance between the root and the third degree of the scale. The ear registers a minor third as sounding smaller and more "constrained" than a major third, which comparatively sounds more restful, stable, and "open." Of course this is also largely a cultural pruduct, in that our ear has been conditioned to consider the major third interval as more "consonant" than a minor- both represent stable intervals and can be resolved towards equally effectively, but at some point far back in history (preesumably during the rise of Greek civilization) it was more-or-less arbitrarily decided that a major intrval was more pleasing than a minor, and the rest, as they say,w as history.