With regard to your last statement about saving the world by unplugging peripherals when turning off your PC (or home entertainment center), I suggest you use one of the new green power strips such as "Smart Strip" that are available from many retailers in the United States.
These strips have a sensor on one of the outlets that you plug your CPU into. When you power down your CPU, the smart strip senses this and turns off a select group of other outlets, powering down your speakers, external hard drive, external USB hub, desk lamp, or whatever you normally use when your computer is running. There are other outlets that stay on all the time.
These smart power strips are a very convenient way to save power and they don't cost much more than the dumb power strips. I use one for my desktop computer and I use one for my home entertainment center, where the tuner is the central device. I can power the tuner on with the remote control and the screen and speakers come on automagically. Neat.