Ask yourself, "What do I most want to improve?" Then seek a tool to help you do it.
By Catherine Price
The Digifit Connect 2, a transceiver you stick into your Apple device, collects data from a suite of wireless sensors—including ones for your bike and sneakers—so you can adjust your exertion level to reach your fitness goal.
The Gruve uses your body's vibrations to measure how many calories you're burning during everyday physical activities (like wrestling with laundry). Bonus: If you sit still for too long, it vibrates to remind you to get moving.
$179 (includes a one-year subscription); Gruve.com
With Withings' Smart Blood Pressure Monitor, you can upload your readings to an iPhone, iPad, or iPod touch and graph trends over the course of a day or a month or a year. The device makes it simple to share your data with your doctor via e-mail.
My favorite feature of the Zeo (the sleep-tracking device) was its alarm: Whereas a traditional alarm sometimes jolts you from a deep sleep (which can leave you groggy), the Zeo beeps at a "natural awakening point" when you're transitioning in or out of REM.