Apple could take over the world in a matter of weeks if they allowed Mac OSX to run on anything. It already does if you research it.
It will not be long before Windows 7 is out, that is expected to be better. Originally they stated Vista would not be released until it was ready, but after 2 years, they had to scrap 90% of it and start over. After a few more years, they just wanted it done so they can concentrate on Windows 7. Vista was barely out the door when they started promoting Windows 7, not the best way to promote your latest and greatest. Scrapping XP is the only way to force people to switch to Vista.
Vista can run decently, but no company is doing it right, they keep selling cheap laptops with it. Laptops that are barely qualified to run XP. If you want to know how to do it PM me.
By the way, XP Home will still be available, the new ultramobile laptops use it (Asus EEEpc), and Microsoft has nothing else that will work. Those being the new trend, they sort of left themselves hanging, they have been forced to keep XP Home or surrender to Linux.