It seems ClamAV/ClamWin wins the battle then. I've used it on servers for some time, and it works like a charm (it's the only one which can update itself via http proxy), it's also used by many big companies, and it's the main anti-virus program for Linux too.
Care to explain first hand features and experience with it? What has it prevented and helped with, truly? Same for AVG, and i'm not talking about it detecting viruses in completely safe programs (as it does frequently).
When I had AVG, it only detected viruses in programs like WPE, and several other apps that had no threat on my side.