If you're a diehard like me who still runs their own e-mail server - perhaps for a few friends and family as well as yourself - you might find Thunderbird's autoconfiguration useful. Even if you only set up Thunderbird on a new machine once a year, you'll be into a net saving of time the second year. And it's especially useful if you have to talk a less technically-minded user through the setup, because all they need is their e-mail address and password.
You simply write an XML file in this format, and expose it at http://autoconfig.your-domain.com/mail/config-v1.1.xml. Thunderbird should then proudly announce "Configuration found at ISP". Sorted.