Actually if you find that you critically and musically analyse any piece you might be interested in, or are playing, then you could figure out which ones are more important to "you." however, this is pretty subjective as I've pointed out. There probably isn't a standard way of testing which forms or composers are more musically worthy, but they probably hold different values of music within different people. Having said that, there are some composers who takes majority of liking musically among musicians, and those you should be aware of. that's about it from me.