Thunderbird is a neat email client that has a small footprint and features some smart ways to stop junk mail.
You can delete junk mail straight away or place it in a folder for reviewing later. The filtering mechanism lets you mark junk that may have been missed, and it will use Bayesian filters to learn over time.

It is possible to customize the toolbars, removing and adding buttons at will, and change how the program looks with themes.
All the popular mail formats are supported and it comes with options for importing mail, address books and settings from Outlook, Outlook Express, Eudora and Communicator.

A big milestone, Thunderbird 2.0 Beta 1, has finally landed for anyone trying to find a great email client that won’t cost them a penny. In a really surprising move only the English-U.S. version is available but I’m not sure if they will add more languages over time or if this is all they have planned for this milestone. From the looks of the release notes page I would say that they are only planning on doing the English-U.S. versions.

Mozilla Thunderbird 2 Beta 1 is a developer preview release of our next generation Thunderbird email client and is being made available for testing purposes only.

You can download it for free:
Windows: Installer
Linux: GTK2 + XFT (no installer)
Mac OS X: Compressed Disk Image

written by Florin C.