I have over 500 win2k3 servers and 1000 winXPsp2 desktops in my organization and they're rock solid. (plus about another 600 UNIX/Solaris/SolX86 servers)
A vast majority of problems that people have with an OS are due to their own, shall we say, lack of experience.
By the way, Vista CAN run on VMWare, you just need another version. It's the same model as now, who run XP home on VMWare?
*waits for rocks and flames