nike plus ipod sport kit

Good workout companion for Nano-using runners; voice feedback; measures useful data such as distance traveled and calories burned; special Nike + shoes are not a requirement; excellent hardware and data integration with Nike + Web site; PowerSong.

Pedometer battery is not replaceable so you'll eventually need to buy a new Sport Kit; available only for iPod Nano.

Maybe it's not the reason to buy a Nano, but the useful Nike + iPod Sport Kit and the data-centered Nike+ Web site will appeal to runners who already own a Nano.