@Cats:

"I'm soooooo happy you are to! I mean, the more people that switch to OS X the more prevalent viruses for it will become!"

Viruses are not "prevalent" on Macs now (like Windows), so how could they become MORE prevalent?

Even if Apple were to gain enough market share to become the number one computer manufacturer in the world, their market share could be as high as 30%. In this hypothetical situation, Windows would be installed on roughly 70% of all computers in the world.

So, even if Apple sells more than all other computer makers in the world, the Mac would STILL be less susceptible to attacks than all of the Windows machines. Security through obscurity does work, and was a pretty smart move on Apple's part not to license its OS (for more than just this reason too).

BTW, the number of viruses for macs has not increased over the past year when Apple has increased their market share and is selling 50% more than they did last year. Apple FTW!