Music visualization is really underdeveloped in my opinion. I've never seen anything I find impressive. The problem is it never really looks very much like the visualization relates to the music I'm listening too. Usually you just kind of see the rythm of the music at most. I want to see something where harmonies look like beautiful patterns, noise looks like noise , and perhaps you could even pick out individual instruments in the visualization. It's really difficult though, which I guess is why it hasn't been done. You need to re-implement much of human audio perception, and then map that to a visual language.