Some random comments regarding earlier posts:
I'm a very active forum user and I must say that Mudcat is one of the best pieces of forum software I've seen to date. It really is intended for communication between people. Of course, a big part of that is because of what it doesn't have - like avatars and jumpieupanddown smilies and other childish stuff. It seems the world is moving toward vBulletin, despite the fact that it's extremely buggy, far from finished, and in many setups, almost unusable.
That said, I just looked at Folk Forums and see that it uses MyBB. As set up there it looks quite clean, but I'll go and register to try it out.
As an administrator, my favourite is PunBB. I've gotten used to the CSS now and can bend it to my taste is some ways. It's very configurable if you don't mind messing with the code. It's also the fastest forum software available. Though I think that Mudcat may be a little better. It truly is a winner in the software department.
Just to put my money where my mouth is, here is one of my forums running PunBB: Princeton Traditional