I prefer to use built in firewall in a suite but otherwise I use either windows firewall or Private Firewall..
Online Armor free Firewall
Outpost free Firewall
PC Tools Firewall
Comodo Firewall
Sunbelt Kerio Firewall
ZoneAlarm free Firewall
Private Firewall
Windows Firewall
I use a Commercial Firewall (Built inside Antivirus etc.)
I dont use a Firewall
I prefer to use built in firewall in a suite but otherwise I use either windows firewall or Private Firewall..
I used to use commercial firewalls but they all seem to get annoying after awhile. Currently I am running windows 7 built in firewall