best open source bb software?

I'm looking to set up a forum, so what would you say is the best open source forum software around? I know of PhpBB and SMF, and I've heard of a few others; UltimaBB, PunBB, but other than that I don't know much. I've thought about going with anonymous image and text boards; in that case Wakaba and Kareha, but I'm leaning towards traditional forums.

So what should I go with?

Thanks.

Punbb is fail.

"Some features that I have so far chosen not to implement are: private messaging, file attachments, polls, linking to off-site avatars, advanced text formatting controls, subforums etc etc."