I have wake on lan going and I actually powered down the other 8 computers when I was not playing on them. So uhh yeah..... not really sure how else to minimize power use here.

I have them setup to boot and automatically run WoW - takes only a few seconds.. I have to switch my monitors from A to B anyway (manual hardware switch) and log in anyway - so it is not a big deal.

Cooling is a big one - that thing runs nearly constantly. 2 Ton AC unit.... 30 Amp breaker.... adds up.