I have been using Norton's Antivirus and Webroot's SpySweeper for nearly five years now, and have yet to get a virus or anything on my computer to harm it. I found through trial and error what works for me with the way I use the internet.
Another software I have tried on another computer, since it was given to me free, is Kaspersky. For a time, and I believe it still is, Kaspersky was the number one rated overall protection for a home computer. I believe it still is since it does have its own firewall.
You can view my extended review of some other softwares that you may want to consider at :
http://www.associatedcontent.com/art..._for_your.html
Hope you find what you need.