@bobjonkman I used #Thunderbird for a while but it just got too slow, even when I told it to stop caching mail locally. I think, but don't recall specifically, there was other misbehavior as well.
Now I use a combination of mutt (logging in to my server), Courier SqWebMail (which supports gnupg), and Roundcube (which doesn't--the plugin for it that's supposed to work doesn't).
I've never gotten along with #Claws-Mail. I also have #Sylpheed on my local system, which I was also unhappy with, but I don't remember if it supports !crypto or not.
Unfortunately with Thunderbird now being officially neglected, there doesn't seem to be a satisfactory client out there.