I have been saying, and recently presenting, for some time that Macs are not subjected to malware infestations because it is not economically worth while to do so. It has now been two years in a row where OSX has been compromised at CanSecWest. This year, Charlie Miller popped a MacBook Air using a client side exploit in about 2 minutes. Last year, Dino hammered on a QuickTime for hours and eventually made it in. I think it is pretty safe to say that the community has a stack of unreleased zero-days at this point, and they just need a small (3 pound?) incentive to use them in public.