Basically, my advice to people who are relatively savvy is not to bother with antivirus. Once antivirus detects anything, it's generally too late. AV can be useful for people who have _no_ clue, but they're bound to get infected anyway sooner or later.
Wrong , if the AV software reacts it's normally because it's actually doing it's job and preventing infection. One or two times a year NOD32 informs me of an infected file and i let it delete it.
At work i often get notifications from Trend Office Scan that a couple of files on some users computer have been infected,detected and deleted.
So in my experience AV software is mandatory
Man is the best computer we can put aboard a spacecraft ... and the only one that can be mass produced with unskilled labor. -- Wernher von Braun