it takes 16 steps to get from aphex twin to billy corgan.
EDIT: Oooh, 18: The Black Dahlia Murder to The Zombies: http://labs.echonest.com/SixDegrees/?start=the+black+dahlia+...
And 23 steps from Kevin Barnes to Goldy McJohn: http://labs.echonest.com/SixDegrees/index?start=kevin+barnes...
Just a nitpick, not meant to detract from the geeky awesomness of the project.