i have the green ipod mini and i've had it for about 3 years! its great but im gonna get a new one soon since mines old and broken. but theres this new thing for the nano thats AWSOME! especially for someone like you whos using it for the gym. heres the link to it:
http://www.apple.com/ipod/nike/
it looks so cool because you first have to have the nano and then you have to get the shoes and chip (comes together) and its cool cause it says how many miles you've ran, how many calories your burning and it chooses songs from your list to pump you up, so it would choose like high, up beat songs. how cool is that???