For what it's worth, in my new computer rig (MacPro, giant 32" Sharp 4K monitor, LaCie "5big" Thunderbolt disk array, Teac class-D desktop speaker amp), I decided to leave the computer on 24/7. This allows CrashPlan to run my backups, but Apple's specs say that it's using very little power. I'm sure the GPUs are completely off, etc. The hard drives definitely spin down when not in use. The monitor turns itself off. The speaker amp is *supposed* to power itself down, but doesn't seem very smart about it. At least class D amps are very power efficient. My scanner similarly stays on but, I at least hope it draws very little current when idle.

Also for what it's worth, I got rid of the UPS I kept for my computer. The poor reliability of the APC UPS was causing more failures than our mains power. Now I've just got a surge suppressor / power strip from Belkin, and there's also a whole-house surge suppressor I had put in last year as well. I figure if the power goes out, there's always switching to my phone.