Avast free edition is best, bar none.

kaspersky fan here!

I have to say ESET Nod32 Smart Security is the best. Its so light on the sys resources and CPU, its hardly noticeable. Using KIS now but its a CPU hog.

kaspersky is very good

I will always go with Avira Internet Security Suite.I think it's is the best antivirus available right now. I am very much experienced with several antiviruses like kaspersky,zonealarm,avast,norton,avg. Kaspersky always catches a false detection viruses which is not good when you are running some keygens which is not infected.
One more think about this kaspersky it always slow down your computer.
Avira is always best whether in terms of catching highly infected viruses or low infected viruses and it doesn't slow down your computer.

i say bit defender internet secuirty.. its wayy better than nod , avg and kaspersky(home version)
kaspersky internet seecurity is ebtter than bitdefender

I use eset nod

in my oppinion,best FREE antivirus (to avoid blacklist license and block AV and the viruses harm your PC) is AVAST FREE EDITION.

for me, nothing better then kaspersky

didn't see sophos or bullguard on your list

sophos is free for all mac users and probably the best one for mac:-
http://www.sophos.com/products/free-...M-CL-Sitepromo