I hope I don't come across as if I'm trying to stir up a debate, but I have to confess, when I'm working out a song, I try to avoid having the same two notes in any chord, a good example being the "0232" version of the G chord. That chord in particular (with that fingering) always sounds just ever-so-slightly out of tune to my ear, with the inclusion of two separate identical-sounding notes (on the second and fourth strings). So I will most often opt for the "4230" version, which results in each note being different from the others. I guess my philosophy is that if we only have four strings to work with, let's maximize our efficiency by having our chords consist of four different notes, and avoid having the same note show up more than once in a given chord. I totally realize that there will be differing points of view on this!