I think I finally found the solution for fighting Spam.
While the Junk Mail filter in OS X Mail.app works quite well, the learning seems to reach a limit, at least with me. Prior to switching to Mail, I had actually purchased SpamFire to use but decided that I did not like having to use two apps in order to catch the buggers. Well for some reason that no longer bothers me and Wednesday SpamFire was updated to version 1.3.2 I decided I would try it again.
It works VERY well in conjunction with Mail, though would also work with Entourage as well as some other less used email apps.
You will want to run the updater once you have this running (Pro/Paid version only) which will download an install many (180+ in my case) rules for stopping spam. I am not sure yet what the period of time is between updates, i would guess weekly or monthly even.
In order to get going you have to set SpamFire up which is really pretty easy. One of the first things you do is import your addresses which immediately get added to the whitelist. You can set up several POP, IMAP or even Hotmail accounts to use which is quite nice. You can set the threshhold level (mine is on max!) and let it rip. You can have SpamFire check manually or on a timer, and after it runs, your email app of choice can then be set to check for new messages. I have mine set to check on a per minute basis and have placed Mail on manual check so that my pop servers do not run into already active sessions. Matterform actually recommends 5 minutes to avoid server collisions. I really have not had a problem with my set-up.
In the main window of SpamFire, you can work with the messages that have been held from your inbox. If you feel something has been held by mistake, it is very simple to add the sender to your friends list and then “Rescue” the mail. When your mail checks on the next run, the saved messages come right through. You can add mailing lists in addition to simple addresses which enhances the functionality quite a bit. Many mailing lists get sent to, or have a reply to set as the name of the list, and you can easily create a filter for them.
SpamFire provides a score for each message captured which is nice, because it allows you to get a better read on how this all works. You can even allow SpamFire to automatically delete messages from known spammers. I have yet to activate this feature, since I am not yet ready to allow for deletion without my review.
If Apple allowed for greater customization or more creative learning with the Junk mail rules, it would not be necessary to use 3rd party software, but until then I think I will be quite satisfied with SpamFire.