Hi:
I do not know how much you know about Ipods. I do not know very much at all. However, what I do know has deterrred me from getting one. As my knowledge is limited I may not be completely right but nobody else has replied yet and so perhaps they can correct me if/when they do:
In an out of the box Ipod setup you would have to channel all of your music files through Itunes (on one PC or Mac) in order for them to be downloaded onto your Ipod and be usable - this is the same for files purchased from the Apple Store.
That said, there is a hack to avoid this (so I am told) which will enable you to use third party software instead of Itunes. However, I have never tried it so I do not know how successful you will be.
Itunes converts files from the format it is in into the format recognisable to an Ipod. Unless you have a relly obscure music file extension I doubt you will have a problem and even if you do there is software that you can buy or free software that you can download which will enable you to convert the file into a file that is more generic and then hopefuly Itunes will be able to convert it for you. Do some Google searches on Ipod hacks and the like and you are bound to find your answers. However, you could save yourself a heap of hassle by buying an MP3 player which is not as restricted as this one - The Creative Zen or the Philips GoGear. I am not suggesting that you should buy a B&O one as I have never used one and would not be able to coment on how good they are.
I hope this helps... Have I even answered your question?