Depends on what you want to do with it.
Home is generally better for simple things (e.g. writing a letter, surfing the web, games for the kids).
Pro is generally a better choice if you plan on doing heavy-duty stuff (e.g. remote connections, multiple logins on network, connecting via Citrix, etc.)
Personally, I'd run XP pro if you can get your hands on a copy...8^)
Thanks for the info.