Thanks for the info Rob!

But I've just checked the Apple website and found out that the iPod's max HD size is 10Gb. This really isn't sufficient. I could have lived with 20, but 10 just doesn't cut it. I don't know how I came up with the idea that there was a20Gb version.... hmmm..could be that I've read that the HD type that is used in the iPod is also available in a 20Gb version, but it seems the iPod itself isn't.... must have got my wires crossed somewhere.
Oh well, I've still got some time before I'm getting this unit. Maybe by then there will be bigger sizes available.