Quote from jeremysnow:
xp pro: a couple steps towards 2000
xp home: a step upgrade from millenium
Nope.
XP Pro is XP Home plus a few things (Remote Access, VPN, file encryption, better backup & restore, multiproc (I think) and IIS). Most likely, you do not need the additional features. Your best bet is to figure it out yourself:
http://www.microsoft.com/windowsxp/whichxp.asp