I heard plenty of things about Anti-Viruses and you know what I have KAV 2010 and I absolutly love it. But of course this is my opinion. Some say it's absolute crap but I think otherwise.
Key features:
Monitors Internet Traffic in real time
Full Heuristic analysis and in-deep scan
The thing I love the most about it, it scans everything in real-time so no worries about viruses and updates automatically every time there is an update but of course it takes a lot of ressources to do so but hey if you have a good CPU go for it or else you can just disable it. The interface is great lots of functions you can add to protect your computer ex: parental controls, Virtual Keyboard (Ex: entering your credit card # is now safe) etc.. and blabla..
Cons:
-Doing a full scan can be long if you have a slow and old computer
Verdict:
Totally better than Norton if you can activate all the handy features but that's only if you have a good CPU and a decent amount of RAM.