Would you still use Mac OS X if it could be installed on any type of PC?
I believe most people move to Apple because they were seduced by the pretty equipment. I'll give Apple that; they make good looking hardware. Others moved to Apple because they liked their iPod. The Mac vs PC commercials have been pretty successful at moving people to Mac.
Apple hardware is expensive. They usually go with the best stuff available at the time of manufacture, and make sure it runs on OS X. Price is the biggest obstacle for most people who'd like to buy a Mac. When money is tight, there's little choice when the laptop PC is $600, and the Mac is $1200. Yes, there is the Mac Mini. That does bring OS X closer to the masses, but the Mini hasn't been that great of a seller. I'd get one, but I'm me.
If you could go to Wal Mart, back in the electronics section, up to the software wall, get the recent upgrade to OS X (we'll call our imaginary version 10. 7.22.1 "Ferral Cat"), take it home and install it on your laptop or desktop PC, would you do it?
If so, why? Besides the malware issues with Windows, what other reason do you choose or prefer OS X over WindowsXP/Vista or Linux?
Knowing me, I'd rush to the Apple store, get me a brand spanking new Mac Book Pro, and have buyers remorse before I got to my car. I'd keep the computer, though. It's pretty.