Hey hey!
Not to poop on anyones parade, BUT, even fully discharged rechargables (of all kinds) do eventually wear out. All rechargeable batteries do need to be fully charged the first time and fully discharged the first time. Also, allowing the battery to fully discharge before recharging, every time, will lengthen battery life.
My point is that it is much cheaper to buy an ipod and recharge it's battery is fuly discharged than to buy new batteries for a different player every year or week (depending on if you use disposables or rechargeables.) As well, the iPod battery is replaceable for under 40$ (in all most all cases) which is a major advantage, considering that the good rechargable AAs cost quite a bit of money to replace in most cases... well in all cases I have seen.
The ammount of money you will save on batteries by getting an iPod is worth it, to me, except that I have no use for such a device.
On an other note... my brother Ben just got an iPod shuffle and he is elated with it's compact size and functionality. I hope he fully charged it before he used it... and fully discharged it the first time he used it.
It is a good practice to fully charge and discharge the battery every time you charge use your rechargable devices and betteries. If you read any battery box or rechargable device instructions, it will say this.