I've used AVG for many years now, and have found it by far the best Anti-Virus around.
I don't use it as a firewall, anti-virus only. I have tried numerous Anti-Virus programs over the years that would not remove certain viruses, in each case as soon as I loaded AVG, the problem solved. I run a different version on each PC, one I paid the top of the range for, the other version is the free version "AVG 8 Free". The paid version seems to pick up more malware problems in my emails, both versions update at the same time, and now I woudn't think of using anything else.
Alphonse43