LED's can last up to 100,000 hours compared to 8,000 for compact fluorescent and 1,000 for incandescent. That averages out to 12 hours of light per day for 12 years. LED's are so energy efficient that they'll actually pay for themselves in a short period of time.
LED's are directional - which means that they only put the light where you aim it or where you need it. Incandescent bulbs just flood the light everywhere - wasting electricity and generating heat.
LED's turn on instantly and run cool, so they're safer to use than fragile, hot burning halogen and incandescent bulbs.
LED's bring a white light into a room. Unlike the yellow light we're so used to seeing from incandescent bulbs, the white light cast by LED's is closer to the color temperature of daylight. The white light of LED's is easier on your eyes.
