Why It RulesThis heart-rate monitor and wrist-mounted coach makes everythingexcept the huffing and puffinga snap. Think of it as the one-handed corkscrew, the clip-on bow tie of fitness equipment. Yes, it's that easy to use. » Don the chest strap to measure beats per minute, and secure the plastic foot pod to your laces to clock pace and distance. The water-resistant unit collects these vitals wirelessly, telegraphing your stats to an oversize display. A glance kept me from over- or under-pacing. » Après-exercise, you need only step within ten feet of your PC to upload datawithout awkward serial-port cords or finicky infrared beams. » The included software archives full-color graphs of heart rate and pace. » Need supervision? A virtual coach can route workouts to the watch. » The final flourish: While sucking data from your wrist, Nike's PC attachment pulses blue light to a heartbeat rhythm. Gimmicky? Yes, but it's a runner's high to use.Hmmm . . .Speed and distance functions (the SDM half of the equation) proved tricky to calibrate.