If you have any notion of doing tech support for a university, you should familiarize yourself with Eudora. It's very popular in academia, partly due to its academic development roots and free availability, but also partly because it's Not Microsoft.
The $50 sponsored version, which many universities provide as a site licensed download for their faculty, students and staff, is a necessity if your ISP doesn't offer good spam filtering and you don't want to switch to a different email client or email system (like Gmail, which is free and does offer decent spam protection as far as I've seen).
Because it's Not Microsoft, I really, really wanted to like Eudora, but I can't say it's my favorite email program. It's fine if you have just one email address, but if you have multiple accounts, you have to go through this rigamorole with setting up separate personalities and it's just not very elegant.
Furthermore, importing settings from Outlook or Outlook Express is not nearly as complete or smooth as it should be. And while Eudora is fine if you're downloading your email from a POP server, it's not nearly as good as other programs at handling IMAP.
And finally, the way Eudora handles HTML and HTML composition just makes me want to tear my hair out. You have no fine control over HTML composition, and it's hard to import an HTML document you've created by hand or in another program. Furthermore, you can't turn off HTML rendering all the way; spammy images still get displayed even though you've told Eudora to turn them off.
It seems that Qualcomm agrees that Eudora of old has some serious shortcomings; they've joined forces with Mozilla and all future versions of Eudora will be based on Mozilla's Thunderbird.