To be fair I feel I have to post this, although this may be the last post for this thread for a while, as I seem to have successfully installed Ubuntu 6.06 on my 250 Gbyte SATA and managed to retain both the WinXP Pro O/S that was on it first, as well as the WinXP Home that is on the 40 Gbyte IDE Drive.
Verified that all 3 O/S's are working.
I went back to Ubuntu tonight and this time I didn't even try to configure the partitions, I just let it do it automatically. There is this one blurb in the set-up I didn't (and still don't) like which says something like "Let Ubuntu find the largest continuous free space" on the target drive for the partition.
Normally, I would assume that the "default" for the automatic settings would be an optimized partition set-up of reasonable (and not excessive) size. The language of this blurb implies the opposite; that Ubuntu was going to create the biggest partition it could.
But while considering possiblity this I decided that the programmers wouldn't have been that presumptuous, particularly when (one assumes) those using the automatic partition feature are going to be relative newbs, who may never use or even may uninstall the Linux O/S shortly after installing. So I went ahead and let it do it's thing and it seems to have done it's job flawlessly.
I still don't know what size the partitions are, so I can't say for sure how much of my 250 SATA got dedicated to Ubuntu. Iguess I'll find out eventually. Plus, it occured to me that I could probably go back into Ubuntu's configurations and change the parition size aftwards. So that's how I came to roll the dice one more time.
So I've taken the first step, chosen Ubuntu as my first Linux O/S and am now going to need to learn how to use it. Given the purpose of this thread was asking for help choosing a Distro, it may be that the thread's purpose is complete.
Thanks again for all the help, advice and "spiritually emotive support".