compact fluorescent lightbulbs
"Energy efficient lightbulbs will cost around £5 - £15 initially, but will pay for themselves in the long run, as they reduce the energy consumption by as much as 70%, and can last up to 13 times longer than ordinary bulbs, with a typical lifespan of 10,000 hours."
"If every household in the U.S. replaced one light bulb with an ENERGY STAR qualified compact fluorescent light bulb (CFL), it would prevent enough pollution to equal removing one million cars from the road."
"Replacing a 100-watt incandescent with a 32-watt CFL can save you at least $30 in energy costs over the life of the bulb."
you can get them at Home Depot and places like that.
we should all make the switch, and get others to do the same. it's one of those things, like eating and sasquatch-hunting, that wouldn't make sense not to do.
http://www.energystar.gov/index.cfm?c=cfls.pr_cfls
http://www.gelighting.com/na/downloads/CFL.pdf
(PDF brochure)