Ipod battery life (both per charge and long term) isn't a secret. I don't own one and I've known about it being an issue, and CNet specifically uses battery performance and replaceability as a comparison point for Ipods versus other MP3 players.

I'd avoid the Ipod (personally speaking) because of AAC and copyright issues before battery performance, though.

"Think of it, if you like, as a librarian with a G-string under the tweed." Clarkson on the Mondeo.