I've been using Norton AV and I came across AVG, so I installed along with Norton, as they do co-exist.

To my surprise as Norton was scanning my computer it passed a virused file without any action, when AVG jumped up and caught it?

What is nice about AVG, are the nice and easy updates.

So I started to use AVG from there on, and I added to that Ad-aware with activated Ad-watch of it.

What does Ad-awre do, is it scans the registry for any virus registry and it removes it (with your discretion). With Ad-watch activated it blocks any attempts of registry modification without your discretion.

I've been so happy with this combination ever since.