There has been a lot of talk lately among Windows Media Center enthusiasts and other Home Theater PC users about getting your computer to go to sleep. The advantage here would be to save a few bucks on your power bill at the end of the month rather than powering beast 24/7. Also, it could help your home be a little ‘greener’. Both causes worth while, no?
Andy VT has but together a nice how-to for getting your computer on its way to cyber slumberland.
My main HTPC uses around 130 watts at idle, 7 watts in standby (S3), and 4 in hibernate (S4) so the case for having it take a nap whenever it can is quite clear. There was a time when getting S3 standby working properly was a black art involving careful motherboard and device selection, registry hacks, and some pixie dust. When Vista came out and even low-end motherboards included full standby support all of that changed; setting up your PC to properly take a nap, and wake up when you need it, is something anyone with a few minutes can do.
Have a look at his whole post for screen shots and configuration.