Oh, and I'm a Microsoft Certified Systems Engineer 
Thats funny

me too, i am certified in NT4, 2003 and 2008, i skipped 2000 "on paper"..
i don't do novell, but i have collegues that do, so i don't know what is the percentage of novell users today, i quit novell at 3.12

They still exist, but its linux based too now (suse enterprise server)
and yes, i know mac based on linux, i have installed adobe on some friends macbook
i like your example with VHS, guess what videorecorder we used to own... right ! a betamax

and since i am a Microsoft man, my customers use Windows server 2003 and 2008, and many of them are on top of VmWare, wich is pretty cool stuff i think.
it also depends on your applications, i mean some applications / servers are only available on windows or unix platforms.