Desktop - Thunderbird

Thunderbird is the desktop client to reach for when you want to own your mail locally and add PGP without trusting a webmail box, and it is free and backed by Mozilla. Understand what it is, though: a client, not a provider, so it inherits the privacy of whatever account you point it at and does nothing magic on its own. The interface feels dated and setup takes patience, but for managing several accounts in one place on a real computer, little else is as flexible.