SOFTWARE IS THE KEY TO SEPERATE THIS ISSUE...
I think that if we installed OSX, Win32 and Linux on test PCs and left them on, the Windows one would crash first, then Mac then Linux. But linux is ok, but support and software is poor. Atleast with OSX the app support is there. But why are we worrying about which is the best OS, they all exist, so let them coexist, maybe even work together. Have you ever looked at the three tier any OS any application anywhere idea by Sun. I think you should check it out it is very cool.
Some of the videos on here may help you understand more,
http://www.sun.com/software/sunray/index.jsp
Basically the first teir are the clients which are mainly thinclients, these then access a SunRay server which can access an array of Application servers. So with 1 thinclient device the user can access many application servers, such as MS Windows Terminal Servers, XDMCP Linux Servers, Solaris Servers, OSX etc... So 1 PC on desk opposed to maybe 2 or 3 if it was done using the 2 teir fat client approach of just servers and workstations.