We're seeing better stability and the ability to roll-off drivers via System Restore is handy; we have some odd hardware floating around and the drivers aren't always what they could be.
Group Policy is extended to cover even more things but this requires an AD domain, and hence is beyond the scope of any small business discussion.
Fast User Switching is a feature that's handy for the scenario where there are a couple or three user for one box, and people don't want to go through the rigmarole of logging out.
Finally, you're running VB6. Known to be ill-behaved in the context of Windows XP.