The ZoneAlarm Free firewall security suite is an amalgam of a firewall, anti-virus software and identity protection shield.
It is easy-to-use in an impressive way. A two-way firewall which makes the PC invisible for the malicious hackers at the same time preventing spyware to send any form of communication that may have leaked from the OS.
Another important feature is that it continuously monitors all programs on the PC for suspicious behavior and alerts you when trying to prevent a new attack.
As an option, it includes a toolbar with a built-in site checker, Facebook privacy scanner, private browsing settings and much more. It also monitor credit accounts and warns you of anomalies. For a free package this service is hard to beat.