I agree with Dennis in all he says above. I have tried Norton, which was OK, but as described above, the support was not good. I also found with Norton, if you were to have other AVs or FWs, they use to fight each other causing many problems to ones system.
I have used AVG, but in my case only the free edition as a trial. Personally I did not rate it much, and in some cases was quite slow in what it was meant to do.
I am using Zonelab now, and have had no problems with the Firewall to date. It spots everything coming in and throws up a warning for you to personally allow it through or not. Anitvirus, I am still on AVG at present, but waiting for the Zonelab Antivirus to give it a trial.
There are many AVs and FWs around, some free, some not. It is really down to you and your system to ascertain which will be the best for you.