OneClick produces two "intelligent" multi-socket adaptors - the IMP and IntelliPlug - that turn off every appliance plugged into them 10 secs after the appliance in the primary socket is turned off.
Take one of our busier desktop PCs as an example of how you'd use an IMP or IntelliPlug. The PC itself has to be plugged into the primary socket and everything else into the slaves.
Turning off the computer would not only eliminate its usual wasteful standby power consumption but also the energy typically wasted while the PC is off by all connected devices - in our case a monitor, speakers, two printers, an external DVD burner, a USB hub, a FireWire hub, two external FireWire hard disk drives and a Skype USB telephone adaptor!