In Real Time: A Hunt for Energy Hogs, Jason Fry did some tests to find out what was really using up the energy in his home.

According to his tests, his other appliances - dryer, cooker, etc - used a lot more energy than the computers, routers and other devices. I don't doubt he's correct.

Light bulbs are remarkably inefficient (which is why I recommend CFLs), and anything that includes both a heating element and a motor (like a dryer or washing machine) at full AC voltage, is going to use a lot of energy compared to the relatively low-end motors and silicon in a computer.