Thunderbird is good, but I'll also suggest Postbox for people looking for alternatives. It's a commercial fork of Thunderbird (so about as "native" as Thunderbi

Thunderbird is good, but I'll also suggest Postbox for people looking for alternatives. It's a commercial fork of Thunderbird (so about as "native" as Thunderbird is), but I find Postbox has a nicer UI, and at the time I switched its local email search was significantly faster. Layout is customizable, you're not restricted to the design (or theme) in their screenshots: https://www.postbox-inc.com/ It has some support for Thunderbird plugins. I use a self-modified version of h.ogi's Priority Switcher to bring back the user-editable priority column that Eudora used to have. (I don't understand how people can process their mail without sorting it by Priority....) Won't be for everyone - it's not open source, not free and there's no Linux version (yet?). Personally I'm happy to pay for a professional / premium email client experience, since it's so mission-critical to my work.