Nice graphics etc are fine but where is the business case for upgrading from XP or other recent OS's!

IMHO MS are going to be seriously disappointed by the business take up of Vista.  Win2k and XP are firmly settled in now, there's also still a substantial number of businesses running NT4, so why go through a major upgrade and major expense, just to provide a new pretty UI?

My users want fast and stable PC's, I'm not convinced that Vista will provide satisfactory levels in either criteria in the medium term.