The argument that Mac's don't have viruses because their market share is less than PCs does not hold water. First of all, the fact that there are zero viruses in the wild, that do not actually require your active, painstaking cooperation to install themselves, should motivate any hacker trying to make a name for himself. In addition to that, you could earn a living from winning prize money for hacking Mac's. Here's another contest for hacking an OS X machine.