Running Norton and AVG on 2nd PC and never had any issues. Each one has a tendency to pick up a virus the other may have missed. On my main PC, I just run AVG now. Which has been working well
I run AVG AV, Zone Alarm Firewall - They are both free and run great... never have any problems, easy and simple updates too. I used to have Norton but that sucked so i wen't with the free stuff
I run symantec corporate edition 10 and zone alarm pro u cant go wrong. I dont know why people say zone alaram is simple if anything norton is simpler.
I dodn't really like AVG because this one time I got a virus over msn messenger that it dodn't pick up but when I scanned with trend micro it came up with 6 virus files but couldn't delete them because it was their online scanner. In the end I had to re format because I couldn't connect to the internet, I have kaspersky now and i like it.