ZoneAlarm:

www.zonelabs.com

Well, its my default FW, need more to say? This FW is really easy to use, it has minimal options (alot of people distrust this) And its not the best when blocking heavy incoming attacks.. But its advantages are: It supports W2k (but not W2k update 1) ITS FREE!! (for personal use only) It blocks incoming and outcoming packets (with a simple method of letting authorized programs only to send packets, alerting the user if a non-authorized program.) It has a Quickbar too, that really makes thing easy sometimes. A bad point is that it consumes excessive resources (when using downloaders like Go!zilla, usually hangs the computer if both the FW and the downloader are not restarted) Its logs are relatively easy to understand Allows in-time logging of the attacking ip's (allowing the user to copy to the clipboard any ip) Its manual is for newbies too
but its not that informative some more advanced features