People who rely on AV scanners have been fooled by the marketing hype aimed at the technically illiterate. They will catch many things that don't matter, deliver an ever increasing list of generic tests (heuristic scanners) that deliver false positives and regularly miss the newer dangerous stuff.
There is no substitute for knowing your OS/Computer, knowing how to secure it, never ever run anything that you don't know and have a disk image of your boot partition as a backup. While there are exceptions, I have the suspicion that virus writers and AV scanner vendors are respectively the demand and supply sides of selling security software that are part and parcel of the same operation. I generally recommend Kaspersky, Eset and the generic Microsoft AV scanners for those who must use them but only if they maintain the correct discipline of not running trash and properly securing their computer. A VM sandbox is also a handy toy if you must run risky things.
