With special silicone tips that hold securely to the ear, Bose's IE2 headphones stayed locked in even on the roughest singletrack. The sound quality? Full-bodied and booming. But be careful near roadways: the surround-sound experience is almost too impressive. $100; bose.com
Got an iPhone? Plug in the Wahoo Fitness Fisica Sensor Key ($80; wahoofitness.com) to connect to almost any ANT+ device. Then download the Digifit Full Functionality app ($15; digifit.com), which, in addition to tracking heart rate and power, syncs with a host of other devices, like Withings's Wi-Fi scale.