I have used a text based email program for years. First VAX mail, then elm, then pine, then mutt for a good 8 years or so. I tried a number of GUI email clients along the way but none of them gave me the flexibility I needed. Then I tried Thunderbird. Thunderbird is the only GUI email program I have tried and actually stuck with. I won't say it is better than mutt but it seems to have all of the same features I used in mutt plus it can more easily handle IMAP mail and attachments etc. But the best part about Thunderbird is the ability to use extensions. Similar to Mozilla Firefox, Thunderbird is extensible and the extensions provide many nice additional features. Extensions I am currently using are:
- Enigmail - To PGP sign and encrypt email.
- External Editor - So I can use vim or emacs (you know, real text editors) to compose my emails instead of the wimpy text editor built into Thunderbird.
- Quote Colors - Colorizes the different levels of > quoting in replies and long email threads. Makes it easier to see who wrote what.
- Mail Redirect - One feature that mutt had which Thunderbird does not have out of the box is the ability to redirect mail. Redirect is sort of like forward but it doesn't change the message body or To: or From: headers so it looks like the email was sent directly instead of being forwarded.
- Display mailing list header - This displays the special RFC2369 mailing list headers.
- Display mail user agent extension - This one is somewhat frivolous but I like to know what MUA the sender is using. It is sometimes useful information.
- Mnenhy - This allows you to define custom headers to display, gives you stats on the built-in junk filter, other nice things.
- Xpunge - Empties the trash and compacts multiple folders/accounts at a time. I have lots of folders so this is a convenience.