It just depends on how often you want music w/ you on the go. When I bought my Generation 2 iPod a couple years ago, I used it constantly. Took it in the car, hooked it up to the radio, jammed on the go, etc. I recently got a Gen4 iPod and I still love it, I just don't use it as much as I once did. I use it for taking large files w/ me mostly now.
There are no real cons of the iPod, IMHO, besides maybe the shiny body that is easily scratchable. If you were to buy one, I'd recommend buying a rubber skin for it so it keeps the iPod nice and shiny.
The iPod works w/ either Mac or PC and is interchangable between the two (I do it all the time), supports firewire and USB 2.0 so it's pretty universal, take it anywhere, plug it in, etc. Winamp has a plugin to support writing to the iPod from within Winamp. iTunes for the PC sucks IMO, but the support is there for the iPod. I think there is a 3rd party plugin for WMP10 if I'm not mistaken.
It's a nice little toy though.