I don't know how many times I've posted here that AVG and Avast are crap.
If you want good AV get either McAfee, Symantec, Trend, or NOD32. These guys always rank well. Between the 4 of them some people like/do not like certain stuff (I hate symantec as its bloated and until recently was 'rootkit'ish).
AVG constantly gets extremely poor detection ratings on indepent AV tests. Whereas the 4 names above usually get within spitting distance of each other.
I always laugh when some AVG loving noob tells me "I've had AVG for 5 years and never had a virus" - my answer is always "how do you know?".... but they don't get it.