I don't agree because it is so easy to get infected even with years of experience. Unless you run all your installs, exe's or whatever in VMs, you are open for attack. And if you do this, maybe it is easier to just have AV at the ready.
But leaving aside IT pros, an average user has nowhere near enough experience to diferentiante a lot of normal situations with suspicious situations, they click yes on everything etc. If you wish to train someone, that frankly can take months/years.
Another problem which a lot of people are missing is the difference between some "soft" malware, classic malware and/or viruses. I've seen more than a couple of computers with half of the screen taken by fucking toolbars/search bars, ad popups etc. Of course, those computers are unusable and everythign grinds to a halt. Even with AV programs saying that all is fine and dandy. So yeah, the user just went to install new java/adobe reader/whatever version, clicked next next next finish and got himself fucked in the process. Sometimes this "innocent" programs will confuse even the most experienced guys with installing shit you don't need but this installed claims that it needs it. Not everyone has 3 programs installed on their computers.
So my point is, nowadays, AV programs are more or less useless as they don't find a lot of malware (licensing or whatever). Yes, I still have it on my windows systems (MSE), but that is for just in case scenario and better to have it for that one time then get infected. But still, people get crap on their computers sideloaded all the time. You can blame the user as much as you want for this kind of infections, but this install X and youl'll get Y which will later download Z and R system has to get fixed somehow.