I have the best Anti-Virus protection of all. Me. If you know what you're doing, and avoid risky sites, and don't do stupid stuff, you rarely get viruses. AV software is hard to distinguish from viruses, they're both intrusive, annoying, and do things I don't want. Since I've never had a virus, I'm pretty sure I'm better than McAfee, which sucks.
I'm not suggesting this for everyone, as I have friends who seem to regularly attract viruses (I don't know how, exactly), but for a lot of people here, AV software isn't as important as it is for the general public.