Agnitum had a nice personal firewall project you certainly remember : Outpost.
I felt it was just giving all the information you needed is a simple yet very useful interface. Open connections, open ports, open applications but really just the way it's supposed to be. Config was easy and you really could see and understand everything that was happening live.
Somehow, other firewalls do a lot in the back, and you don't always know what's going on or find about it way later.
Unfortunately & on many versions I had too many issues with it and always had to switch back (to zonealarm at that time
). I wish they would continue the project and make it better.