http://www.millennion.org/bbs/
Just migrated over to PunBB from Phorum. As much as I love Phorum, it was taking me too long to get everything just the way I wanted it. There's still a few mods I want to add, but aside from that I'm pretty happy with it.
PunBB is without a doubt the best mid-size BBS around. It looks great and it isn't bloated with useless features. I'm sold.