what is it supposed to be? for those of you who have one, what kind of battery life do you get? for me, it seems that i may have a nano that doesn't work properly. i run a lot (basically everyday) and it seems after about 2 runs, i have to charge it. so it seems like i'm getting at max 2 hours, probably less. now i do have the volume up quite a bit, but not all the way up. do you think i should take it back to the apple store?