A "dumb phone," and ditch the smartphone.
It made me think about the bandwidth hog the corporate email was too, even for casually checking. So I removed that account from the phone. When I choose I can listen to internet radio or surf the web and if I use too much the annoying balance notification is a good indicator that I should be doing other things.
But these days it probably doesn't matter what phone I use, as I leave the thing at home as often as I take it with me. Now I'm no longer on-call, via SMS, I just don't need the distraction.
Then I go into the kitchen at work and see people getting coffee while checking their email. wat.