The Nike + iPod Sport Kit is a must-have for any avid runner, offering a simple way to maximize your training regimen. The kit includes a tiny sensor that attaches to a running shoe (special sneaks are available with a built-in pocket under the insole). As you listen to music on your iPod Nano, the sensor monitors calorie burn, pace, distance and time. The system transmits verbal updates throughout the session. After a workout is complete, the data can be transferred to the nikeplus web service, where you can track progress and set new goals. For heart rate monitoring, add the Polar WearLink+.

$29 for the Sport Kit, $19 for the shoe sensor, $69 for the Polar WearLink+