For several years I have had LED flashlights. They produce a bright white beam of light and use far less power than a regular incandescent flashlight. (I even found a flashlight that uses the same Lithium CR123A batteries as my Pentax 67II and Sekonic Light Meter.)
I was most impressed therefore when I saw LED lightbulbs on the shelves of my local store.
Toshiba LED lightbulb
The great thing about them is that they use even less power than a compact fluorescent bulb. The bulb I got produces 565 lumens of light (similar to a regular 60W bulb) while using only 6.9W. The main disadvantages is that they are still quite expensive, for example the bulb I got was 3,880 yen (US$40) but this should pay for itself over several years due to the lower running costs.
Household lighting consumes a huge amount of electricity. The introduction of LED lighting provides a simple way to reduce the amount of energy we are using. Manufacturers of green products need to be supported by consumers, so next time you are at the store consider getting an LED lightbulb. It may not be a panacea for environmental problems, but it is another step in the right direction.
TRAVEL 67 : Chris Willson Photography 
I just saw a whole row of these at Yodobashi yesterday. Coolest version: one where you can set the light output -and- the color, from blue-white to orange-red. In a few years we may be able to regulate the full spectrum. Makes for some very interesting decoration possibilities if you can set and change the color tone of the light any way you want it.