We've covered LEDs before. Now reserachers are claiming a breakthrough which may bring the day when we light our houses with the little diodes closer still:
"Until now, all lighting systems, especially incandescent bulbs, generated more heat than light. But our 99-percent efficient reflectors for LEDs makes them the first candidate for light-bulb replacement that generates more light than heat," said Schubert."
This would be truly impressive if they can cross the more-light-than-heat line, because it means _massive_ efficiency increases. He mentions doubling LED output, but it'd have to be be closer to triple. Currently LED's are less efficient than fluorescents, and the most efficient lighting out there is sodium-vapor (usually only used for streetlights & cheap gymnasiums because of its ugly spectrum.) But even these only put out about 25% of their energy as visible light. If these guys get over 50%, they're taking the best efficiency out there and doubling it.
(By the way, efficiency numbers are hard to understand with lighting, because they're never quoted as a percent, but the # of lumens/watt. There're good reasons for this, but basically if you take the lumens/watt and divide by 683, you get real-power-efficiency.)