According to VB, NOD32 is the best AV (32 Passes/3 Fails) AVG is 9 Passes, 20 Fails!!! Avast is 13 Passes, 19 Fails. Norton: 28 Passes, 6 Fails. Kaspersky: 27 Passes, 13 Fails.
So if going for free, go for Avast or Antivir. Antivir is really good except for the fact that its updates are HUGE to download and generally the update system is considered buggy!
Kalpersky has the *BEST* detection rates.
You should not go THAT much by VB anyway. Cause their testing methodology is wierd! I mean if a program misses 3 viruses, it is awarded pass and if one detects ALL viruses and just gives ONE false positive, it is Failed??? I seriously dont get this!!! I mean i prefer having one false positive to 3 virus infections anyday!!!