I was getting frustrated with spam in my mailbox (surprise surprise) so I searched the AT archives knowing there are many smaller thread with few responses... I gathered some of the more recommended suggestions to make a definitive thread to hopefully help people in the future 
Programs:
Outlook 2003: has built-in filter/algorithm that is supposedly good.
Thunderbird: Very powerful email client. Windows, Linux, and OS X clients.
Proxy solutions: Program runs in background, receives emails, your client gathers emails from it. Mail server -> Proxy -> Client.
Bayesian filtering: Learns from your mail.. Adapts to and builds on your inbox.. "smart" filtering
K9: Standard POP3 only (no AOL/MSN). Bayesian implementation. Runs as proxy.
PopFile: Like K9...
Spamassassin: Used to be good. now not as effective. Is rules-based, but also employ web spam-database. Has EUDORA plug-in, and proxy version. Biased towards Perl and Unix.
Mailwasher: Free version available. 30$ Version has more features, and work with Hotmail/MSN/IMAP/AOL
Spampal: Spam tagged with header. You configure your client to filter those mails at will. Employs configurable blacklists--you can select which lists to use. Also has whitelisting feature. 100% Free
Cloudmark Spamnet: Was free. Now is subscription based. Outlook version with 30 day trial. Outlook Express beta version free.
Spam Interceptor: looks fishy to me.
Spambayes: More popular recent suggestions. Bayesian. Outlook plugin, IMAP, and Proxy. Will need PYTHON installed for Windows clients!
I personally think Spampal looks most appealing. Will personally try and report back later
If I made any mistakes please let me know. Also if you have good suggestions feel free to list them.
Programs:
Outlook 2003: has built-in filter/algorithm that is supposedly good.
Thunderbird: Very powerful email client. Windows, Linux, and OS X clients.
Proxy solutions: Program runs in background, receives emails, your client gathers emails from it. Mail server -> Proxy -> Client.
Bayesian filtering: Learns from your mail.. Adapts to and builds on your inbox.. "smart" filtering
K9: Standard POP3 only (no AOL/MSN). Bayesian implementation. Runs as proxy.
PopFile: Like K9...
Spamassassin: Used to be good. now not as effective. Is rules-based, but also employ web spam-database. Has EUDORA plug-in, and proxy version. Biased towards Perl and Unix.
Mailwasher: Free version available. 30$ Version has more features, and work with Hotmail/MSN/IMAP/AOL
Spampal: Spam tagged with header. You configure your client to filter those mails at will. Employs configurable blacklists--you can select which lists to use. Also has whitelisting feature. 100% Free
Cloudmark Spamnet: Was free. Now is subscription based. Outlook version with 30 day trial. Outlook Express beta version free.
Spam Interceptor: looks fishy to me.
Spambayes: More popular recent suggestions. Bayesian. Outlook plugin, IMAP, and Proxy. Will need PYTHON installed for Windows clients!
I personally think Spampal looks most appealing. Will personally try and report back later
If I made any mistakes please let me know. Also if you have good suggestions feel free to list them.
