The poll should be multiple choice. Anyways, I didn't vote, because I use different firewalls across all my systems. Windows Laptops = Outpost Windows Desktops = Windows Firewall Mac = Build-in Mac Firewall.
I used Outpost many years ago with a lot of problems, Look'n'Stop was fine but was abandoned.For the last 6 years I've been using Windows Firewall (inbound only) without any problems with XP, Vista, and Win 8.
Various - Sygate, Online Armor and Emsisoft Internet Security in different snapshots. Also, DefenseWall Personal Firewall across all snapshots, since I am still running XP