For years, I have used and recommended ZoneAlarm - and it is an excellent firewall. But it seems, IMO, the makers of ZoneAlarm, Check Point, did not learn for the mistakes of Norton/Symantec and McAfee and, like them, concentrated on adding so much "fluff" to ZoneAlarm that it now has become a huge resource hog, and has a significant impact on performance.

Sunbelt Kerio Personal Firewall is very popular and used by many of my colleagues. However, like Dan, I have been migrating to Comodo and am very pleased with it - and the price is great too.