I bucked the Ipod trend and got a Hi-MD player from Sony instead. Sure, it's not as sexy but you get about 25 hours on a AA battery, and 1Gb on a removable disk. Considering it's only $200 to get the basic one, I think it's money better spent.
I read an article on how to replace the battery on an Ipod. Although it's not too hard, it's not something I want to consider "having" to do.
Now, in comparison to the Shuffle, I think the Muvo from Creative is a better product. Although I love Apple (my first computer was one) I don't really think they are doing anything radical with the Shuffle besides riding on the wave of the Ipod.