I like to know how far I have run or biked, my per mile pace, and the calories I have used. I even like to map out my favorite routes and save and share those routes with other athletes. I use a simple and free tool – MapMyRun.com – to track my workouts. The three MapMyRun.com features I like best and use most often are:
1) Satellite mapping of running routes. I usually run on trails that are not on the standard map but can be seen with the satellite map zoom feature.
2) Gear tracking to track the number of miles I run on each pair of shoes. I usually replace running shoes after 250 miles and MapMyRun will alert me that a pair of shoes needs replacement.
3) Weekly leader board Reports are emailed to me each Sunday that show my workouts compared to my running and cycling friends.
If you really want a lot of data about your running, cycling, or cross country ski workouts check out the Garmin Forerunner 305 GPS Receiver With Heart Rate Monitor. Even though it is a bit hefty on the wrist I like all of the data it generates.