I don't use software firewalls, so could not comment, however I have been using clamwin (
http://www.clamwin.com) free anti-virus scanner, it's updated a lot, I started using it because I was already clamAV on my BSD boxes for scanning email before delivery to mailboxes, and also scanning samba shares.
If you're looking for more of a norton feel, you can get a free personal anti-virus from
www.avast.com that is not a bad option either.