This is a mildly interesting topic. Basically, because so many people leave their electrical gadgets on standby when they are not in use, it is using around 7TWh of energy – the equivalent to two power plants worth of production.
From my experience, this is something made much worse by PC users – who often leave their equipment switched on for hours at an end (overnight etc).
It is interesting to think that a little lifestyle change (switch off at night for example) could have an actual significant impact on your fuel bills and in the long run the whole planet.
Further reporting available at http://news.bbc.co.uk/1/hi/sci/tech/4620350.stm