There are a few good (if not better) and free alternatives to Linux XP:
ReactOS is a good free alternative. It's Linux/FreeBSD based distro that simulates the windows experience and has good Windows driver and application support

Not to mention the fact that it's the fastest OS I've seen to this date.
Maybe installing a distro like SuSE or PCLinuxOS and then getting CrossOver Office (which runs a bunch of modern games and MS apps) might be a better way to go?
It's probably best to get something that doesn't lie about it's features... Notice how the MS Word program in the screenshots say "OpenOffice.org" -->
http://www.linux-xp.com/gallery/
Also their use of non open-source drivers from ATI and NVidia violates the Linux kernel