I have upgraded my system several times while running XP and the only time I needed to call Microsoft CS was once when I upgraded motherboards. That included two seperate video card upgrades, neither of which needed a call.

I guess I don't see what the big deal here is. I won't be upgrading to Vista until the performance is benchmarked significantly past XP, but for people worried about upgrading this seems to be a loosening of the rules currently applied to XP if anything.