Best antivirus program?

This has probably be asked a million times but I don't really see it in the threads I'm able to scan:

Does anybody have an opinion on the best Windows antivirus programms out there? Being a Linux guy myself I'm blissfully clueless about Windows security; Need to help the GF,who uses Windows though..

Everybody has their favorite. I prefer Symantec. We use it at work on ~2000 machines. I believe it is also the market leader.

i've heard some grumblings about avg.


I use NOD32, seems to work fine.