Two of the replies mention FastMail, which for all I know might be nice, but FastMail still seems to be in its infancy (though perhaps growing fast) when it comes to securing customers' data. See the recent
https://news.ycombinator.com/item?id=15853477I've been using Gmail for over a decade. I've been getting in the habit of using a purpose@mydomain email for as many signups as I can (that for now all forward to my gmail) so that the impact of a random Google mess up that disables my access to my account is lessened, but there's still no service I trust more for my email's security and privacy apart from Google's algo-eyes (that offer me some features I appreciate anyway). Maybe that trust is misplaced and we're only a few years away from a Yahoo-level incompetence reveal, but I doubt it.
If there was a way to setup a local mailserver that can peer in a hierarchy with more trusted mailservers (so that I can send email with reasonable confidence it won't end up in a spam folder), and have encrypted buffers stored at those peers for when my local machine is offline and can't accept deliveries, I'd do that. Maybe it's possible with Urbit.