THe iPod spec has gone up and up, but the prices have remained the same, if not gone lower.
You dont get a Dock with iPaqs anymore for example.
It is just another revenue stream that Apple have gone after - accessories are big money! Buy an iPod for $300, buy a power adaptor for another $40, along with a nice Sock, a extra cable, the Dock, remote, cables - all in it's going to cost about $500!
I have the new 30GB iPod and as you know, it does not ship with an AC adapter. I honestly don't think that it's necessary. Even though it may come in handy when traveling, more than half of iPod owners probably don't use theirs. So Apple is just trying to save a little money, cuz we all know how they are so poor from selling $300 music players.