i got a 20gig 4th gen through one of those free things a while back (only sold out random internet people i knew : P...they were willing) anyway, upgraded using education discount to 4th gen 40gig for 70 bucks total.
Needless to say, the ipod hasn't left my side once since I've gotten it, I take it everywhere and use it all the time. I'm pretty sure I'm in love with it.
However, I couldn't afford to pay full price for one under normal circumstances. I've never had any experience with other brands, but from what people say it's probably not worth the price, but regardless the ipod has been a dream to have/use.