Well i would recommend Outpost Firewall, i have used it before, and no problems with it. I just haven't installed it yet, because i was waiting for a full win 7 software. But now it is full compatible with win 7 in all flavors. By the way, if you use avast with Outpost Firewall, i recommend to disable Outpost Firewall realtime scanner, because it will slow down avast.