Sygate Personal Firewall
Full user review
"Best firewall I have tried."
Requires little or no configuration. Doesn't get in the way as some other firewalls do.
No longer being actively developed.
Sygate was bought out by Symantec several years ago. Symantec discontinued the product, which is too bad because it is still the best firewall software available.
From time to time I have tried some of the newer ones out there, and I always end up disappointed. The tried-and-true Sygate Personal Firewall does not disappoint.