HIya Bill, Welcome to the forums.
It sounds like you have a fairly nice computer, once you get that HD replaced. I was looking at the Linux XP Pro website and I must say they have a pretty good deal going on, it even looks like WinXP! I think you should have a look at some LiveCD's before you purchase Linux XP Pro.
The LiveCD List
I highly recommend Ubuntu, Knoppix, and MEPIS for the New Linux users.
Just download one, and burn it to disk.
You don't even need a hard drive to use them, just pop it in the CDrom drive, reboot and you have instant Linux! You might find something you like more than Linux XP Pro. In my opinion, they are only selling you the "WinXP" themes and updates, both of which are free (for most distros) by the way. As for Internet Explorer being run on Linux XP Pro, you can run it on any Linux distro with special software.