I would suggest the complete security suites from either Bit Defender of Checkpoint Software. The suites contain anti-virus, anti-mailware, firewall, download protection, antispam, parental controls, anti-phishing in ne well functioninga nd unobtrusive package..... and no remembering to do manual updates like on the free alternbatives
If you download the free trail and don't buy at the end, you will get e-mail "reminders". Eventually the price drops about 45 days after expiration and that's the time to jump .... I have the suites installed on about two dozen computers and they require 0 administration time.
Avast is a good free antivirus. I use malwarebytes alongside avast and it works great.
I just use windows firewall for windows 7. It is better than the XP firewall cause it has both inbound and outbound rules where XP had an inbound only firewall. Some people will disagree with me I am sure but the 7 firewall works good. But I am not against a security suite, most probably have a better firewall. Also if you have a decent router it may have its own firewall.