Re: Terri Bozzio
It does look like overkill at first glance, but my understanding is that the kit is tuned to a chromatic scale on the left side (the piccolo toms) and a diatonic scale on the right (regular toms). Likewise, the cymbals are arranged tonally, along with the percussion stuff (not sure if those are crotales or what...)
I accept any drummer's right to have as big or as small a kit as they want/can afford. It IS a shame to see a drummer with a massive array of drums and cymbals that don't get used... but hey, if being surrounded by a bunch of superfluous hardware fulfills some need for them, more power to 'em.
Bozzio, from my understanding at least, makes use of every drum, cymbal and widget.