All the antivirus stuff always seemed to cause problems and was a pain to use so we would end up running without any antivirus software. Back when we keep a real PC around for testing we would usually go out and buy a new PC when ours got so infected that it was impossible to use any more. We usually went through one or two PCs each year. We would buy whatever was the cheapest box we could find since it was only for testing stuff.
Now my PC is just a 3 gig folder...
I still run WindowsXP for testing my stuff but since now that I can do it on my Mac by using
Parallels my PC is just a folder on my Mac's hard drive so when my PC gets infected I just throw it away and make another copy of my fresh unused PC that I keep on my Mac's hard drive. Total time spent replacing my PC now is under one minute at zero cost.
I also run Debian Linux this way and I guess I should setup a Vista PC too.