And on the subject of "competing operating system", if you're thinking of sticking with XP, you'd better upgrade soon. I'm getting a new system built at the moment, and after searching around online, it's getting very difficult to find any place that even offers XP as an option. And the guys as the computer shop I go to are saying odds are good that inside of six months, you won't be able to buy XP at all. Unlike in previous years, you won't have a choice between a 9x vs NT flavor (or XP vs 2000). This time around, Vista is all MS is offering.
I have to assume that XP will still be available for those of us that build OEM systems, so my company will still use it for the security systems we build, but if you're wanting XP at home, MS won't be giving you any alternatives this time around.