The Creative Nomad Zen Xtra (40GB) is a MUCH better value for money than the ipod. Apart from offering more Gigs at a lesser price, the Zen has a removable battery, which ipods do not. Essentially it means that when your ipod battery dies (which can be in as little as a year and a half) you have to pay Apple $120+ to replace a $30 battery.... whereas in the Zen Xtra, you just buy another battery and change it yourself just like in any cellphone. This also allows you to carry extra batteries for long trips. (The battery life is also much better than that of ipods). Other than that, it has a better sound than ipods IMHO, and it DOES NOT tie you into one format like Apple does with AAC..... you can use mp3s, aacs, wmas... whatever....
However the Zen is not without its share of problems:
#1) It is not as stylish or compact as ipods..... but IMO if you choose a ipod just because of style, you are not exactly the smartest consumer.... The size, however, makes a slight difference, if it is important to you.
#2) It needs drivers to be installed on every computer you want to use it on.... doesnt work just like a plug-n-play external hard drive... so I suggest if you need it for that, to buy a small USB pen drive and carry the driver with you.
#3) The bundled software is bulky and a little icky to use... but their are a number of free or cheap 3rd party alternatives.
#4) The Headphone jack is known to have a problem which requires repair by soldering... for more about that check https://pcpages.com/thebishop/nomadfix/
That said, I still think that the Zen Xtra is a much better value for money than the ipod, and you should go for this option, unless you are a style junkie and the ipod name is more important to you than the performance of the player.