As much as I truly hate to put down an open-source product, vB is definetely the best in the business. Besides, DevBB (formerly XMB, since XMB was taken over by a group of people that aren't quite as skilled or ambitious as those before them) would make a better contestant than phpBB anyway.
vB is the first and best PHP forum software out there, and I have yet to download or see any forum software coded in PHP or otherwise that can truly compete with it. Although I'm usually against shameless promotion of commercial software, vB is the definete best of them all... it's got more features, better speed (vs. ASP & Perl boards, as well as a few PHP ones), and a huge list of satisfied and high-status clients.
Err, without furthering the overly-biased statment above: If George decides it's right for the forum, it's probably right for the forum, and this time I'm completely happy with the changes made ;) (as opposed to my mixed feelings about the removal of the p-word)