I have been a user of Comodo Personal Firewall for some time - v2.4 under Win2K, then v3.x under WinXP. I liked 2.4 a lot but it no longer cuts the mustard. Although v3.5 is one of the top-rated firewalls (see Matousec), I find it a bit obtrusive - too many pop-ups. So I tried the latest free version of Online Armor - also reviewed at the above Matousec link - and I am most impressed. There is also a straight comparison of Comodo vs Online Armor here. Online Armor is produced by http://www.tallemu.com/ - a company with which I have absolutely no connection.

Just wanted to alert others here to what looks like a very good product. Comodo has been mentioned and recommended here, but I have not seen any reference to OA previously.