I don't rely on anything. I have KIS on this machine and avast on others. They are both turned all the way up. I see the occasional warning from my AV that something was killed during a download. YAY for web scanning!
I scan regularly with a *few* various scanners(entertainment purposes mainly).
TH a2 PestPatrol AVG/Ewido Housecall(for kicks) -- Think outside the Fox... Opera