If Microsoft is shipping Windows XP SP1 (kinda like Windows 98SE), then it'll be slipstreamed and the majority of the fixes will be included. If this costs extra, you can slipstream it yourself. It's really simple, and you can find the article <A HREF="http://www.btvillarin.com/windows/links.htm#OffsiteGuid..." target="_new">here</A> (Misc. Offsite guides).
Me and Toey are having trouble with IE with SP1 slipstreamed, so <i>perhaps</i> it might be best to get the original Windows XP version, then install the updates <i>before</i> SP1. Then, use <A HREF="http://grc.com/xpdite/xpdite.htm" target="_new">XPdite</A> or something like that to finish it off. (That's what I'll try next in my troubleshooting spree.)
I've just did what I said I would do. I clean installed Windows XP, without SP1. Updated everything pre-SP1 and added the XPdite fix. After about an hour of operation and web surfing with IE, it's been pretty good.