I'm in the beginning stages of some major upgrades to the machine running the web/mail system here, every major piece of software on the back end is being upgraded, and the hardware is seeing some major changes as well Gone will be the old G4 system, in favor of a new Intel Mac, and a whole host of software upgrades for the new hardware to bring everything current with the latest releases (MySQL 5, MovableType 4, Courier-IMAP 4.1.3, Postfix 2.4.5, pcre 7.3, PHP 5.x, etc, etc). Oh, and of course, Mac OS X 10.5, when it ships, hopefully next month.
The plan at this point is to prep the new hardware, install all the software, then migrate the data from the old server, followed by much testing to make sure that everything is working as it should be. If all goes well, shortly after Mac OS X 10.5 ships, I'll be able to wipe the drive and install all the latest bits and be able to go live in early November. There should be no noticeable difference (unless I play with MovableType a bit!), but my UPS will have a lighter power load to deal with, at least. :)