acemarch: Oh I know they can work great, I've been an IT Technician for almost 8 years now, but I prefer to spend the little bit of money on a solid product that I can have faith in, at the cost of what... one less new release game a year? The prices are affordable on decent software nowadays, so IMO that little bit spent on protection is worth it. (Suddenly sounds like a condom advert....)
As a fellow IT Technician (over a decade now) I have to strongly disagree with this. I have yet to find a commercial anti-virus product that is more effective and better on your system resources than some of the free alternatives out there. There are some that are equal to their free counterparts, but better... not so much. They are definitely not worth the money spent on them in the slightest. The only environment where a commercial product makes any kind of sense is in the corporate world, simply because most of the freebies don't offer the kind of control over a network of protected machines that the commercial products do.