I’m with @Nagathex, my understanding of left and right is that the left hand path is centered on the self first and the right hand path is centered on others first. LHP people i know use an internal judgement criteria for determining their actions. RHP people i know use an external judgement criteria. Black and white magick are the same deal, as i see it. Black magick for personal gain, white magick for the gain of others.
Which is why i dont know ANYONE who is only one or the other. Here are a couple of excellent posts on this topic from a while ago
http://forum.becomealivinggod.com/t/mastering-the-godhood-concept-no-laws-that-bind/6172