I really like the Polar S710. It gives you speed,distance, max speed, avg. speed, altitude, temperature, calories burned in addition to heart rate. The stored info can then be downloaded to your computer via an Infrared reader. The computer adds up your mileage, calories, number of exercises and time on a weekly basis.
I wear it for every workout I do, weights, spin, Spinervals tapes, swimming, the occassional step class. The lap counter has a large button that's very handy when swimming for interval work.
Veronica