We use Mcafee Virusscan Enterprise 8.5 + the Antispyware plugin managed by ePolicyOrchestrator and rarely see actual infections in fact maybe three in two years and that's protecting 500+ systems.
I use nod32 over anything, definition wise it seems to be about the same as avg but i find it uses less resources and when its updating you dont get a popup at the most inconvientient time, as the slogan says, set it and forget it...well now im begining to sound like a walking advertisment for nod32. Just my 0.02$
i tried panda, norton, symantac, avt, spyware doctor and many other but the NOD 32 is the best antivirus i ever used... and using still..
software is the antivirus state, it's when that software becomes hard/firmware that it becomes dangerous, more so in the input stage.
NOD 32 is the best and lite anti virus for my slow old PC, it safe me fro various other anti virus products. i think its ideal for slow computers such as p2 or p3.