Research has found LEDs are comparable not only in brightness to the old incandescents, but much more efficient than even compact fluorescent lights. LEDs are also built to last 15 years, compared to five years for CFLs and one for incandescents. "The LEDs are costly now, but the price is dropping very rapidly. So we have a very bright and cool and thrifty future," Chu says. Supporters say saving $10 to $11 a year in energy costs more than makes up for the initial outlay. Analysts expect LEDs to drop to $20 a bulb within two years, which is about wh...