I use a modified Monobook theme in a Debian package of the current stable DokuWiki. Not publicly accessible.

The wiki is used as a business manual, a place to record system settings, references, all business documentation except accounting, project management, and as a central interface to various offline search interfaces (the main ones are in the left-hand pane). I also use it as a Knowledge-base for my OTRS ticketing system.

Dokuwiki has all the features I've ever needed (and more). Great design and an excellent community behind it. Light-weight, simple, and easily extendible. I can't think of another piece of software that I've used as long (a decade) with so few problems over so many upgrades. It saves me a huge amount of time and is the greatest productivity tools since the shell.
Many thanks to everyone at DokuWiki for it, the forums, and the mailing list.

The only thing that might be special about my setup is the various search interfaces built into it.

SFITCS