Pointless
I figure if you want to have new toys you need to buy the new toy. Thats Microsofts problem in trying to be a do all. It's really simple. If you want to continue to use XP programs then keep XP but don't blame anybody when a developer writes a program that will only run on Windows 7.
I find it stupid that they are even doing this VM thing with XP. One word "Upgrade* or stick with the old and out dated OS you've come to love. I love Vista, I will love Windows 7 even if i have to upgrade to enjoy all that it has to offer. New is good, New is fun. Life is about experience even if its a new shiny thing like Windows 7.