[kevkrom]

I should have phrased my question better - it’s not the email client that concerns me, I’m looking for suggestions for a back-end service that plays nice with IMAP/SMTP so I can have the convenience of a webmail account without having to deal with their websites, and preferably one that doesn’t treat my email as a corporate data-mining exercise. (Short of end-to-end encryption, I don’t expect to avoid the feds data-mining my email.)

[TomGuy]

a back-end service that plays nice with IMAP/SMTP so I can have the convenience of a webmail account without having to deal with their websites

I have been using POP Peeper for years to read my Gmail and Yahoo email without going to their websites.

IIRC, I had to open Yahoo Mail in the browser and use the 'keep me logged in' option for POP-Peeper to work with Yahoo mail.

The program can also be set to use your preferred email 'send' program.

http://poppeeper.com/

[Windflier]

I think you should look at email programs like Thunderbird. If you’re connected to the internet through an ISP you can set up your own email system without the need of going through a website portal like Yahoo, Google, or any of the rest.