Dave Caddick's excellent original post here ...
... not forgetting then GPS you can wear on your wrist! The Forerunner 205 and the 305 unveiled at this years CES in Vas Legas.

Both the products provide information in real-time to the users and help keep track of their fitness regime and goals.
Garmin Forerunner 205 and 305 are waterproof and come in a new design where the GPS antenna wraps around part of the wrist helping it to have a better view of the sky. GPS receiver sensitivity has been enhanced as well this time around.
The display on the two devices can be customized, and data can be segmented according to your needs. AutoLap automatically records lap data at a specified time/distance/position while AutoPause will pause the lap timer if the user drops below his configured pace. Through MotionBased.com, users can download and share courses with other users.
In addition to these features, the Garmin Forerunner 305 has a heart rate monitor that delivers data to the user's device and this data can be used to generate post-workout analysis.
The Forerunner 205 will be $249. The Forerunner 305 will be $349, both will be available in February.