It's unfortunate that simple public key encryption, which has been easily available for many years, is still seen as untenable and "super-paranoid." Any email client, or better yet Gmail, could easily implement it and make it virtually transparent to the user (when both ends of the email are using such a client, obviously).
I apologise if you have mistaken my meaning! I certainly hope we don't take wider scale encryption to be untenable, but it is very certainly untenable for a single person to use the web in a meaningful way with normal people while maintaining that every single email needs to be encrypted.
That's still wholly untenable for the real world, but not all paranoid people live in the real world per se.