LEDs can double as data transmitters, save even more energy
Here is one more totally awesome reason that we should be switching out incandescents for LED lightbulbs: a new technology means a single LED can transmit more data than a cellular tower. Professor Harald Haas demonstrates in this TEDGlobal talk:
The lightbulb is flickering on and off too fast for the human eye to detect. So while we see just … light, a sensor sees a binary on/off stream it can translate into 0s and 1s. You can also turn the lightbulb "off" and still transmit data. (The secret is: it's not actually off! Our eyes are just really not all that sensitive.)
For super extra bonus points, this method of data transmission is extremely energy efficient, even putting aside the inherent efficiency of LEDs. As Haas puts it, "This is data through illumination … The data transmission comes for free."