What's the best Mac wiki?

Hello TUAW readers! I thought I'd turn this out to the community as I'm shopping for a good wiki for a project I'm starting at work. Jay, who is big into wiki projects, is recommending TWiki although he is currently using Wikka, but I thought I would get the best feedback by polling the always insightful TUAW readership.

The intention is to have a wiki I can run off of whatever Mac box I decide to stick it on (most likely an easily replaceable Mac mini) with secure access for people on an intranet, but making all the info available via the Internet as well and with a handful of moderators. What do you think? What's the best Mac wiki?