NOD does a solid job, on viruses, but it isn't the best when it comes to other threats.
www.av-comparatives.org click on the comparative link on the left, view February/May results.
Rokop is well respected and you don't need to read German to be able to interpret the chart. Nice thing is that they indicate system impact for each app on the bottom of the chart.
http://www.rokop-security.de/main/article.php?sid=757
http://www.rokop-security.de/main/article.php?sid=693
You want the best, KAV 5.0 is it IMO, based on my testing, reading and the fact that they have decent, responsive support. Fully functional 30 day trial can be downloaded at
www.kaspersky.com.
You buy a free AV, you get what you pay for and shouldn't bitch if you get infected.
Regarding VB, it is ONE resource, but remember it isn't the end all. Good example is that BitDefender failed the most recent test. Why? 1 False positive. I'd rather have an app that identifies a potent threat than miss it.