Yes the mac is hardware, but viruses run in the operating system which runs on top of the hardware. And the operating system on mac's is OS X, which isn't (currently) affected by viruses.
Lawl.Macs can have 3 OSes, but Windows machines can only have 2. It's nice that Mac users get more choices.
I've set up several Intel Macs to triple boot Mac OS X, Windows XP, and Slackware Linux. Just manually repartition and use rEFIt instead of Boot Camp's control panel.Lawl.
Err. Macs cannot run 3 OSes at a time though. It can only boot between two.
Also, PCs do have more than two OSes. They have Linux, Windows, BSD, FreeBSD, Unix, ReactOS, AROS, Darwin, ClosedBSD...
Also, Linux has many distros.
Macs still rule though .