I used Norton personal firewall for a while, but when I checked the log, I was recording no events. Tech support was useless. When trying ZoneAlarms Pro, I recorded 2-3 events a day (i.e., things looking at my IP address, which may or may not be hackers), so I stayed with that. It seemed to be capturing more things. But, it may have just been computer or Norton setup problems on my end. I still use the Norton Utilities and Norton Antivirus.
As an aside, yesterday I set up a Linksys 802.11b wireless Access Point and Router in my home yesterday to wirelessly extend my DSL broadband line. To my surprise, I found the LinkSys supports integrated "enhanced gateway security" using ZoneAlarms Pro, by selecting that option in the LinkSys operating system and the ZoneAlarms Pro software (see the top of the Advanced Firewall settings). It apparently brings some of the ZoneAlarms Pro functionality beyond my PC to the LynkSys device. Exactly how useful this is, or exactly what it is, I have not yet determined. The LinkSys device does not include the same support for Norton Personal Firewall.