A Mac.
Lawl, More seriously, I run a Virtual Win.7 On my Mac, And the only program I have is Malwarebytes' Anti-Malware,
What choobs don't understand is that an Anti-Vir won't save your ass against Nicely-Coded stuff, So I just keep an anti-Malware against basic crap, Witch doesn't eat ressources at all, And I am cautious with the rest.
My opinion
Mely