I have been using NOD32 on both my business PCs for some six or seven months now. In that time EVERY virus has been caught, quarantined and deleted. AVG never managed a 100% success rate, nor did Norton, nor even did F-Secure, though that was comfortably second best. Avast; I ran that for all of two weeks, so it hardly got pushed and it would be impossible to form an opinion from that brief time.
I used Norton a number of years ago and wouldn't go back to it (expensive and slowed my machine).
In the time I have used AVG and Avast (on different PCs) Avast has intercepted a few viruses while I have been surfing on the net. AVG has detected nothing but then as i said i am careful and both PCs are virus free.
At £17.50 a year the reputation of NOD32 is tempting, after all I'd hate to be using the helpdesk because I have become a victim.
We all to assess the risks and make up our own minds however healthy discussions here can help inform those in need
You may also want to consider system overheads. NOD32 has the smallest system footprint of any fully-featured AV despite the strong heuristics; Norton is notoriously heavy; F-Secure is actually quite heavy; AVG is okay and runs happily on older PCs.