I used to use Avast, but I went looking at ZoneAlarm again for a possible free firewall and was surprised that they give their firewall + antivirus away for free now. So, I'm back on ZoneAlarm (haven't used them in years). They only give a popup about once every week or two asking if you want to upgrade. Not too bad. At least it's not as bad as AVG. The last time I used AVG, it gave popups multiple times a day.