Yeah, I personally gave up and embraced HTML email, so I can't really use some of the nerdier clients I like. Right now I'm pretty OK with Thunderbird - knowing that I _could_ switch any time I like is somehow good enough for me, it appears.

At work we use Thunderbird for regular communication but I sometimes have to dig into large exports (100+ gigabytes, up to 10 per mailbox) and mutt is very fast and responsive, so I've found an incantation for the config that strips the styling and layout.

What I don't have yet is the same for my bulk import to SQL database, but I'll probably figure something out in the next project where we need to analyse large amounts of email.