The Pebble E-Paper SmartWatch is about to hit the market (later this month?) for $150. The watch shares data and tech with your iPhone or Android phone and has the ability to install watch apps.
Say you are a bicyclist, you can use the Pebble Watch as bike computer to keep track of your speed, distance, elapsed time, etc, The watch uses your phones GPS for precise tracking. Similar apps are available for runners as well, track your pace, distance, control your music, etc,
Some other features of the Pebble E-Paper SmartWatch include caller ID, music controls for iTunes, Pandora, and Spotify, an accelerometer, Bluetooth, and a battery that lasts about 7 days.