Love the Reg!
I just gotta love the Reg and the vast majority of their Mac-hating readers. So many readers, so much misinformation.
Where to start - Macs are the only PCs available that run both Windows and Mac OS X natively. So that means that all of your Mac programs, all of your Windows programs, oh, and all of your Linux programs will ALL run on your Mac.
Macs use many of the same components as PCs. Like Intel CPUs and FSB (front side buses), ATI video cards, nVidia video cards, same RAM, same hard drives, same monitors, same peripherals. Doesn't seem all that closed to me.
Similarly configured Macs and PCs from major manufacturers usually cost within £10 of each other. Go here for more info - http://systemshootouts.org