Garmin Forerunner 305 (which I got on sale at REI). It is a bigger than I thought, but not really too heavy (until you've ran for over a mile and a half and are ready to collapse). I love having all this data on my wrist while I run. It can track real time distance, time, pace, speed, and so much more. It can even map your routes and stores all this data for 1000 laps in the watch itself.This is my new running watch, the
Using the Garmin Training Center, you can download the data for archiving purposes and to see graphs of your performance. You can also create custom workouts and the watch will alert you at each step. It comes preloaded with a ton of workouts already to get you started. The watch also has alerts you can turn on to tell you when you've reached a certain distance or time, as well as when you go above/below a specified pace or heart rate zone.
Here is a screenshot from today's run. Click on the image to see the details in the bigger version.