spammy post to make after 3 posts but ... It depends on what "plug-in's" you need for what your forum deals with. My forums need to hide contact details etc, be reasonably anon, not all allow that. Why do you ask and why not build up a post count before such open ended questions ? vagrant
There has been so many posts like these before, just check the Forum Management forum and you will see a ton of these topics.
VBB is neater, IPB is cooler - if that makes any sense If you need that your users will have excellent individual blogs then its IPB without any doubt. If not then perhaps VBB. Both have also very good social profile embedded. Best is test demo sites EXTENSIVELY to come up with your own conclusions. With either of these you cannot be a loser