My transition to living with Mozilla Thunderbird as my email client is complete, now that I’ve discovered the bliss that Seth, er, I mean, is the Debian packaging of enigmail (and, for that matter, T-bird; for some reason, I didn’t think it was packaged until I started fooling around today). The anti-spam features are easier than futzing with Bogospam, the IMAP support with the dovecot server seems pretty robust, and it seems reasonably fast for my purposes.