http://greenpages.indoff.com/ 

Of the $250 billion spent per year on powering computers worldwide, only about 15% of that power is spent computing - the rest is wasted idling.  40% of the energy used for electronics is used while these devices are turned off.   Obviously, just because a device is turned off or not in use, it doesn't mean that it isn't eating up electricity.  In fact, even when a computer is switched off, the surge protector can still draw energy - up to 75%

• Programming your computer to sleep after 30 minutes of non-use can cut power demand up to 90%
• Stepping away for longer than 30 minutes?  Turn the computer off and unplug the surge protector.  (Booting up again uses the equivalent of only two seconds of run time and won't hurt the hard drive).
• Monitors are especially big energy drains.  Be sure to turn them off after 20 minutes of non-use.
• Printers, scanners and peripherals that are only used occasionally should be unplugged until needed.