I still have no mailserver running here. (I’m now forwarding all my other accounts through GMail.) I’ve wanted for a while to set one up, but it has to be good.
I just came across Funambol, which is apparently an enterprise-grade server package for syncing mail, PIM data, etc. with mobile clients after installing a client-side package on your mobile device (Palm, Blackberry, and Windows Mobile devices, as well as generic Java ones, are all supported.)
And then, of course, you’d want Roundcube for webmail. It looks good, lets you search your messages, and doesn’t log you out after you finish composing a lengthy e-mail. (Are you listening, OWA?)
Oh, and DSpam for Bayesian spam filtering with a good web interface.
What caused this whole thought process was someone asking if there existed a service that basically offered what I’ve just described. He stated he wouldn’t want to pay more than $10 per mailbox. (Hosting six mailboxes at that rate, I’d be making a profit!)