I've got a 3rd gen 8gig. Present from work. Nice for free and nice to play around with but I don't think I'd part with money for one.
Not sure about the new gen but the battery life on mine is appauling.
What would you be buying it for?
For music I much prefer using my ipod nano as I can operate it easily from my pocket and it has a decent battery life.
For games I much prefer the ds, my favourite game to play is 'find the unsecured wireless network'
I find it a little too small for watching videos
Half of the functionality and software is there to remind you that you've not got an iphone.
Maybe if spent a lot of time around free wi-fi networks with no access to a computer and not much else to do.
Apart from the above, I love it.