Apple's traditionally ran on a PPC chip from IBM/Motorolla. Recently however, due to IBM being a bunch of pricks, Apple has switched from the Power PC processors to x86 Intel chips. The other hardware is pretty standard, most of it just made to a little higher standard.

With the PPC to Intel switch you could potentially run the new mac OS on your regular Intel desktop. However, I'm sure apple is going to use alot of hardware recognition and checking programs to ensure that you're using only Apple made computers.