if i am actually doing XP installs, i just use nlite. my XP disk is SP1, so i integrate the two new service packs and just install at that. works well enough for me.
That's rather missing the point, unless you don't bother with any updates published after 6th May 2008.
I have a complete Autopatcher setup on a USB stick which covers Office XP/2003/2007 as well as Windows XP and Vista... it's an absolute godsend not having to rely on someone else's (possibly slow/unreliable) Internet connection for critical updates whenever I have to format/reinstall their OS for whatever reason.