In The Light

From the article entitled "How Many Lightbulbs Does it Take to Change the World? One. And You're Looking At It."
The impact of a compact fluorescent lightbulb:

What that means is that if every one of 110 million American households bought just one ice-cream-cone bulb, took it home, and screwed it in the place of an ordinary 60-watt bulb, the energy saved would be enough to power a city of 1.5 million people. One bulb swapped out, enough electricity saved to power all the homes in Delaware and Rhode Island. In terms of oil not burned, or greenhouse gases not exhausted into the atmosphere, one bulb is equivalent to taking 1.3 million cars off the roads.

How really long they last:

Swirl bulbs don't just work, they pay for themselves. They use so little power compared with old reliable bulbs, a $3 swirl pays for itself in lower electric bills in about five months. Screw one in, turn it on, and it's not just lighting your living room, it's dropping quarters in your pocket. The advantages pile up in a way to almost make one giddy. Compact fluorescents, even in heavy use, last 5, 7, 10 years. Years. Install one on your 30th birthday; it may be around to help illuminate your 40th.

And the company that is determined to change the lightbulb industry:

A year from now, chances are that you yourself will have installed a swirl or two, and will likely be quite happy with them. In the name of conservation and good corporate citizenship, not to mention economics, one unlikely company is about haul us to the lightbulb aisle, reeducate us, and sell us a swirl: Wal-Mart.
In the next 12 months, starting with a major push this month, Wal-Mart wants to sell every one of its regular customers--100 million in all--one swirl bulb. In the process, Wal-Mart wants to change energy consumption in the United States, and energy consciousness, too. It also aims to change its own reputation, to use swirls to make clear how seriously Wal-Mart takes its new positioning as an environmental activist.

Much more in the article about business partnerships, CFLs being a classic example of creative destruction - like how digital music transformed the music industry - and how one light bulb you buy may in fact impact the world.
I replaced four normal lightbulbs with CFLs in my house tonight.