When I first bought my 2G iPod, Apple did not yet have a battery replacement program. So, I had to accept that the battery might die and the iPod would be useless as a portable device. I was OK with it because I could always leave it tethered to my sound system in the living room. It can shuffle by album which none of the CD jukeboxes I've ever tried out or read about can do.

Now, Apple has an official battery replacement program in place as do third parties. So, I wouldn't worry about it much. I sold my 2G to a friend that is still using it on the original battery and my wife uses a 3G iPod and I have a 4G iPod. So far, no need to replace any of the batteries.