I think this one may only appeal to programmers, but I've just switched to the mutt e-mail client, and it's great. It's a text-based email reading and writing program that runs in a terminal window. I find it's a lot faster way to deal with email than the webmail or Outlook-like mail clients I've been using since about 1998. In a way, it's like a really powerful version of the old pine client from the 90s.
The reason I say it may only appeal to programmers is that it takes a while to set up initially, involving writing some configuration files and setting up two other programs (offlineimap and msmtp). But it's worth it in the long run and, also, msmtp looks like a great way to automate the sending of email -- something I think could save a bunch of time with university admin jobs.