Standby Power

Standby power also called vampire power, vampire draw, phantom load, or leaking electricity, refers to the electric power consumed by electronic appliances while they are switched off or in a standby mode. Entertainment systems are prime examples. A typical system consisting of a set top box, VCR, TV, stereo, and amplifier can consume 50-75 watts or more, even when not in use. In study’s performed by the Lawrence Berkeley National Laboratory indicated that Standby power consumption accounts for approximately 10% of total residential electricity consumption in America, adding up to more than 3 Billion Dollars in annual energy costs. The easiest solution is to plug all the devices into a power strip, and then turn the power strip off when not in use. With i-sockets’s accurate monitor data, you can detect the leak and kill the standby power.

From wiki http://en.wikipedia.org/wiki/Standby_power
A 1998 study estimated that devices on standby accounted for about 5% of U.S. residential electricity consumption, “adding up to more than $3 billion in annual energy costs”.[5] A 2000 study said standby power accounted for around 10% of household power-consumption.[5] A 2004 United States Department of Energy report found that national residential electricity consumption was 1.29 billion megawatt hours (MWh).[5] 5% of that equals 64m MWh, about the output of 18 average power stations.

The British Government’s 2006 Energy Review found that standby modes on electronic devices account for 8% of all British domestic power consumption.[6] A similar study in France in 2000 found that standby power accounted for 7% of total residential consumption.[7]
Similar findings were made in other developed countries, including the Netherlands, Australia and Japan, with some estimates of the share of standby power consumption over 10%, highest approaching 13%.[5]

Standby power for each device http://standby.lbl.gov/summary-chart.html