I suppose you use webmail supplied by a corporation. With all your old messages available for scanning when they or the government see fit. Some of us are not okay with that.
You suppose incorrectly. Leave your assumptions at the door.
I use Fastmail as my email host, and Airmail as my client. I have one eye on Nylas N1 as a potential future cross-platform email client.
Instead of what exactly? Eudora? Windows Live Mail?
Airmail. Or, if you're able to get into the closed beta, Nylas N1.