I have a 4th gen 40 gig, and after about 3 hours of playback, my battery meter is at half. I'm just playing shuffle songs at a low volume, not skipping through or anything. Seems like the battery's going pretty quickly. Should I take it to an Apple Store? Thanks Also, if Apple gives me a new one, do you know if they'd let me upgrade to a 60 gig photo and pay the difference between the 40gig and 60?