In-ear headphones from Isotunes that both fit well and have good sound isolation. They have clever buttons that you can use to quickly skip songs or answer a phone call.
From Amazon
ISOtunes XTRA 2.0 Earplug Earbuds: EN352 Bluetooth Hearing Protection, 27 dB NRR (Noise Reduction Rating) Sound Isolation, 79 dB Volume Limit, Up to 11 Hour Battery Life
Acme Tools
ISOtunes XTRA 2.0 Bluetooth Earbuds 27 dB Safety Matte Black
GearFreak.uk
ISOtunes - Xtra v2 Noise Cancelling Headphones
OnBuy
ISO Tunes: Red/Black ISOtunes IT-25 Xtra 2.0 EN352 Earbuds Itm