Scott,
Hopefully, we are helping. I am a little confused by your last post, but I will try to add some things. First, Universal Restore would not be a good option for cloning a drive. You have to use it with Acronis TI Workstation Echo, so you would have to buy that. It is really designed for a different purpose.
Certainly, Acronis' Imaging Backup software could be used. But, Acronis has one program which is specifically designed for transferring data as a bootable image.
http://tinyurl.com/Acronis-Migrate-EasyIt is rather likely that your new machine will have a motherboard that supports SATA drives along with IDE drives.
You lost me on your licensing. To transfer your license from your retired machine would mean being able to activate it. As Geoff says you won't be able to activate even though it is only being used for the new computer and not the old. Microsoft may allow it. You would have to call. But, you only change so many hardware devices (there are charts for this), before the OS will not recognize the other computer. You would be able to run Vista Business and downgrade to XP if you want. You can't run them both at the same time either on two computers or one. The main place you lost me was on the "I already have one of these left over from the new machine I bought back in Nov." Sure, you could install XP onto the new machine, use the CD key and then activate using Vista's key. But, then you would have no OS on your Nov. machine. Boy, this was much easier when you just had one license and one machine.
When you say your desktop CPU has some business programs and data on it, are you referring to the machine itself, e.g. the hard drive?
I am not sure that cloning your hard drive and transferring it is going to be the way to go. When I think of cloning and transferring it is more like when I upgraded my Seagate 7200RPM SATA drive to a WD Velociraptor 10,000RPM drive. (sweet drive!) So, here I am with a relatively new computer with two SATA drives, and I am cloning the Seagate OS/applications/data directly to the WD. So, after transferring in less than an hour and reformatting the Seagate, I am left with a much better hard drive with no activation or driver issues and even extra space with a second drive which is better for backups.
In your case, you are looking at transferring data from an older drive that is compatible with the hardware and drivers, etc of the other PC and swapping it over to the new drive in the new computer.
Personally, I agree with Geoff. If I am understanding correctly, your new computer will come with an OEM Vista Business. You could stay with that and just transfer your data. Yes, you would have to install your applications again, but you would have a clean machine.
Or, you could grab any XP Pro CD (if the retailer didn't include one) and install clean. It's not going to take that long to transfer your data whether it's 5GB or 15GB. Just copy it and go have a beer and come back.
We have all reformatted machines when the registry gets clogged and no I/We don't look forward to the install. But, it can be made easier.
I would simply partition the main drive into two partitions with the OS on the first and all of your data on the second. Install all your applications and get all the settings the way you want them and make an image of the first partition. You can go back to that image anytime you wish. Of course, new programs will be added, and it gets hard to keep up with them. But, you can leave the D:\ drive (partition) alone with all of your data and point My Documents to it. Make a list to every step.
Finally, and this is what I do, but you don't have to. I use a second 500GB drive or larger to put local backups on (as well as external). Then, I make a folder called Applications, and I copy EVERY CD to it and EVERY download with every license and key in the individual folders. This way you can copy that drive to another one when you build a new computer or use it if you reformat that one. You can do that to an external USB drive, but it is still faster to install from a direct drive, plus you can make backups of it. This means you do not have to hunt for CDs and open and close the CD/DVD drive every time.
So, in summary, I would start clean. But, you should learn to clone/image drives at some point or clone VMs, etc.