I did a test with my Panasonic portable CD MP3 player recently and here's what I came up with. The Panasonic is a portable CD player with two tiny displays, it reads CD's as well as MP3's, has mechanical parts which move quite a lot during playback, and it runs on two AA batteries. During the test I used NiMH rechargeable batteries and played it on 75% of it's volume with eq on and believe it or not it gave me well over 60 hours of playtime, (it will play even longer on alcalines). Now, I'm sure there is a reasonable explanation why iPods (which have no moving parts and a better battery then two AA's) can't do that, and I would honestly like to hear it from someone.