With my WiFi off, I just set my music to play in alphabetical order and then left the Touch alone (so the screen did power off). I used it very briefly for a few things (related to screen testing, so I briefly played a video podcast clip and was on its internet with WiFi on), but probably less than 30 minutes total. The iPod shut off after playing 23.2 hrs of music. When I turned it back on this morning, I got the warning that it was down tot 10% power, even though I had gotten that warning last night (so it didn't realize it had more power than it did). So I very unofficially forecast that the music playing capability of this thing is probably around 25-27 hrs once you let your battery drain to "reset" it.