They should have included all Windows OSes simply for the absolute worst design feature/idea in an overall OS design - the Registry. Not only is it a global data structure and subject to security vulnerability (not good for the system), its very nature is prima facia evidence of Microsoft's incompetent design in OSes. Just running RegMon from Sysinternals.com for real-time changes to the Registry boggles the mind.
Security needs to be designed into a sytem as a forethought, not an afterthought. And we are all paying for that. Vista will be no better, maybe slightly, but at $450 a pop not too many folks are going to be beating a path to their Vista door. The research OS, Singularity, with no Windows roots is the only long term chance MS has to survive in the the future. Of course, MS's profits are really generated by its applications which would then have to be redesigned to not use the Registry.
I rest my case - I'm a long term Unix/Linux user and only tolerate Windows because its there, for now, at least, anyway.
-- Tom