I say just don't use any firewall...
Let's face it, firewall is supposed to interfere with internet traffic. Ones that doesn't do this doesn't work. Ones that does this cause problems. I've never used any kind of firewall, and nothing ever happened to my computer for the past several years.
I'm involved inanime fansubing, and often distribute copies via bittorrent. So at any given time, dozens of ports are open, with literally thousands of active connections. This makes it impossible for any kind of firewalls to operate. But lucky, I don't need it. Latest security updates and a moderate antivirus does the job. Coporate America plants fear in the public so you would buy their firewalls.
Seriously, viruses are blocked by antivirus and security updates. The truely new and well built ones that hijack existing ocnnections can bypass firewalls anyway. Hackers don't hack at your computer all day. These losers have better things to do. The world does not revolve around you. The whole internet is not out to get you. Drop the firewall already... -_-