I use all of these together... Avast! ZoneAlarm Spybot: Search & Destroy AdAware SE All of them together work better than Norton or McAfee, I've tried them all.
I'll recommend AVG free edition as well. Norton/Mcafee are bloated to the point of unusable these days. ZoneAlarm free version of the firewall is also a great addition. It can take a little time to setup properly so all your programs work correctly, but it is worth it in the long run.
ad-aware se & spybot s&d are for spyware removal not anti-virus. i use avg free as does most of my customers. http://free.grisoft.com/doc/downloads-products/us/frt/0?prd=aff
I use avg and bitdefender free edition. Every now and then one catches something that the other doesn't. Just don't have both running at the same time.
Sorry for the lack of clarification and any confusion if any. Zonealarm is of course a firewall as well.
he left but did show up under another nic called jeepnut i think. check the neph thread in safety valve