LED's have taken the battery-powered lighting industry by storm. Headlamps, flashlights, you name it: all come in LED varieties. It's not hard to see why: LEDs use very little power, enabling battery life figures above 100 hours; they are quite bright despite this fact; and, what's more, for all practical purposes they last forever.
However, for home lighting, compact flourescents are all the rage these days. These bulbs are a big step up from incandescents: they last around 5 times as long (though they get dimmer towards the end of their life), and they use about a fifth as much power, as well. However, they have their flaws as well: they're expensive, and as they contain mercury, they need special disposal.
Incandescents are to compact flourescents as compact flourescents are to LEDs. An LED lightbulb would sip power and last practically forever. From an environmental impact standpoint, they'd be a huge win. So where are they? Why is nobody working on this?