My Mac is totally virus free!
Oh dear, frantic clicking of fanbois and Apple deniers alike. Calm down, it's not what you think.
That is, my Mac is free from iOS5 viruses.
For the rest I have taken great care to make it compatible with all OSX, Windows and even Linux malware by means of Virtualbox (I hate Bootcamp, because that means I can only get one type of malware at a time).
Yet, the machine still hasn't got any malware, because I do not execute applications I don't know (there is something to be said for the walled garden) also because I like to see file extensions, I don't visit odd websites and I keep up to date with the latest patches. The latter is a complete pain in the rear, whereas OSX hits the Net once every week and then very occasionally finds something to pick up, the Windows (XP) VM is unusable for half an hour if I have the temerity of not letting it work for a week because of all the OS patches and its own anti-virus update. The Linux Mint VM less so, that's more at OSX level of update overhead.
Oh, and I never bought the "virus free" crap and I have anti virus installed. Call me fickle, but I prefer hard facts and proof over marketing fiction (it's great fun to wind up fanatics in any camp asking them to prove their claim that the platform is virus free - it totally frazzles Linux users, for instance)..
Now, on balance this means all the platform living on this box are OK - because the same sanity applies to all. It's simple: if stick your appendage into dodgy places you're sure to catch something so don't. Apply common sense instead of believing any stupid marketing drivel - works every time..
By the way, anti-virus is an "after the event" measure - prevention is better. AV will not help you at all with zero day threats, and I have seen one remain unnoticed for over 2 weeks, despite me submitting it to some AV vendor contacts I have and getting it back 2 hours later with a note that I was right calling it a virus.
So there.