Motorola S11-Flex HD Stereo Bluetooth Headset
I’ve been through a bunch of Bluetooth sports earphones, and the S11 is the only pair that:
(a) hasn’t broken in the first month
(b) has enough Bluetooth range to cleanly pick up music from a phone in my pocket
The sound quality isn’t the greatest, but these hold on firmly during running and get the job done. The little USB waterproof door broke off literally the first day I had these, so I keep a little flap of electrical tape to keep the USB port covered and away from my sweat. My only other complaint is that the beeping noises these things make when adjusting the volume is deafening, so I usually keep the volume all the way up on the earphones, and adjust it as necessary on my Pebble watch or phone.
Battery life is excellent.