If you mainly use your MP3 player at the gym, getting a pair of headphones that both fit securely and offer some sweat resistance is key. The $40 Nike Aero Sport Headphones certainly fit the bill there, and although music doesn't sound great through this set, the sleek and sweatproof design may appeal to some.
The Nike Aero Sport Headphones are sold in the Apple Store, and they fit in excellently. Two sleek, white, shiny plastic discs contain flat speaker drivers that rest on the outside of the ear and stay securely on the head even during vigorous activity.
These are attached by a thin, plastic neckband that loops over the top of the ear and then behind the head. A single thin, white cable extends from the middle of the neckband so that you may keep the cord behind your arms during activity.
The earphones are extremely sweat-resistant and easy to clean thanks to their plastic design and rubber earpads. Also, we like that they don't block out outside noise, since that makes them appropriate for street-runners as well as gym-goers.