Macs use an ultra-modern industry standard technology called EFI to handle booting. Sadly, Windows XP, and even the upcoming Vista, are stuck in the 1980s with old-fashioned BIOS. But with Boot Camp, the Mac can operate smoothly in both centuries.
Good for Apple that they don't have to worry about backward compatibility on old hardware. I also remember the pre-2002 era, when Mac OS still lacked memory protection and preemptive multitasking. How "1980s" does that sound?