Sure, it can tell time, but the TomTom cardio watch is really meant to track the beating of your ticker, with a built-in heart-rate monitor that works without an uncomfortable chest strap. It breaks data down into five intensity zones, so you can get the most out of your workout, and its large, one-button-control display screen shows you distance, pace, calories burned and more. Runner Cardio, $270, Multi-Sport Cardio, $300