A seatbelt is a simple, preditable mechanism that functions without impeding the driving experience. Anti-virus software which is a complicated, unpredictable mechanism that significantly impedes the computing experience.
I find a more viable approach is to be careful with the OS install (not install untrusted stuff) and also to make it expendable. Data lives on a single-purpose unix host and is regularly backed up so I can do a predictable, quick, low-effort reinstall and be back to operation in a couple of hours.
An outcome I've wanted but not done - computer lives behind a router which is set up to make active monitoring and managing of traffic easy. Product idea - consumer-ready but geek-friendly router with powerful but easy-to-use tools that doesn't suck. Interface should be live so that you can see the traffic coming and going, and there should be controls to allow you to open up and close access to different sites. Stand-along system with a profile a bit like a sunray, plug for commodity keyboard and monitor.
The author of that page did not come to the conclusion "do not use antivirus software because it will make your computer slow" but rather ask consumers to make an educated decision about which software to purchase based on their detection rate.
Malware will also slow down your computer, and could result in your personal information being stolen. If the choice were between waiting an extra few seconds for my computer to boot or having all of my files accessible to people I neither know nor trust, I would choose the former.
"You're doing it wrong" personified right there. If you're using MacAfee or Norton, that's like wrapping a seatbelt around your neck (as those numbers show).
If you're working without at least common-sense anti-virus protection, you're going to deserve what you'll eventually get.
I just kicked Norton of my wife's Vista PC, thanks to Norton's own "Norton Removal Tool".
I'd like to know what your definition of "common-sense anti-virus protection" is, though. Apart from "don't download/install anything from untrusted places".
The trick for both is using it.