In all seriousness, if you are behind a NAT router, the firewall that will cause the least hassles and incompatibilities is the Windows Firewall itself. In any version of Windows and without any third party modifications. To me,a firewall should be that and only that. Software that monitors connections (primarily incoming) between your machine and the rest of the world. All the other stuff like HIPS and program monitoring are , in my opinion, not only not the job of a firewall, but too obtrusive and almost always a complete waste of your time while using your machine. For a business or Agency that would be a prime target of attack, yes, you need more protection. But the average home user? I don't think so. Just make backups of data you wouldn't want to lose, install the Antivirus of your choice, and enjoy your computer time with no needless hassles from third party firewalls that go way beyond their scope.
