I've just gone through the same faff, although luckily the machine I bought was licensed to downgrade to XP Pro, and even had (sort of) an XP install. I had to in essence recover a backup of the XP install, and it seemed to take twice as long as a normal XP install, but it does seem to work fine, once I deleted half of the normal "extra" crud that manufacturers think we need.
(Like a "free" 90 days license to Nortons, when I've got free access to a corporate version).
Vista does seem to be masses of pretty faff. Even with the short time I used it, I got extremely pissed off with the repeated requests asking if I really wanted to do something. Yes, I sodding well did, that's why I just clicked the mouse button. <fume>