Standby for vampire power
'Vampire power' is the theatrical name for standby power - chosen for the fact that appliances in standby slowly suck power even when the appliances aren't in use. Standby power can account for as much as 10% or more of your electricity bill, and unfortunately some of it is almost unavoidable.
Devices go into 'standby' mode so that they can be switched on again using remote controls. The power is used up in power supplies which have to keep the system ‘alive’, ready to respond at all times. In a television, a small receiver is constantly on, drawing a tiny amount of current.
Satellite TV systems, garage door openers and computers in 'sleep' mode can all consume power surreptitiously - they are not necessarily big dollars, but they all add up. Some devices are far worse in terms of the standby power they consume than others.
How to deal with standby power
The easiest way to prevent vampire power consumption is to turn things off at the power point. This ensures that no power at all is going to your appliances, although it also means that your remote controls won't work, and may be a pain if your switch is somewhere inconvenient (like behind a TV cabinet).
A number of different products are also available nowadays that are designed to make things more convenient - either by automatically switching all of your devices off when they're not being used, or offering a way to 'extend' control of your power point to a more convenient location with a master switch attached to a cable.