In Princeton, the town's effort to reduce energy consumption began with an assessment of the municipal buildings' energy use. If this makes sense for a town, then maybe it makes sense for a home.
The Kill-a-Watt is a useful tool for getting a handle on some of your energy use. (They are available over the internet, but not locally.) It can test anything that plugs into a regular wall socket, up to 1850 watts.
Here it is in action, measuring how much electricity a toaster oven uses. 1400 watts is 100 times as much as a florescent bulb uses, and about half as much as a small electric dryer.
A toaster uses lots of energy but for a very short time. Press the red button on the right side of the Kill-a-Watt meter and it tells you how much energy the toasting of toast took--a grand 0.05 kilowatt hours. That's about one penny's worth of energy--about the same as having a 50 watt light bulb on for an hour.
Obviously, toasters are not toasting the planet, but check other appliances and you're sure to find some unnecessary drains on energy. The device is particularly good for finding and measuring the energy used by electronics even when they are off. An October 21, 2007 post gives more info on what various appliances use.