My electric bill is usually $50 - $60 (U.S.) every month, which is probably about average for the U.S. This also includes a 100 Watt bulb for my turtle that is on about 12 hours per day.

I also charge my iBook at work and use is on battery at home. I use it for work quite a bit, so I don't find this unethical.

The front panel board and one of the built-in USB ports on my home G4 are shot. So, I have to unplug my Pro keyboard and plug in an older keyboard with a power button to turn it on (this is how a got my "non-working" G4 for free). My USB 2.0 card doesn't support keyboard power-on. It's a minor inconvenience, but it's enough to keep me from turning it off at night. It's also nice if I need to access it from work.