The Geek writes: "I often regret using bbpress instead of something more solid like vbulletin or phpbb."
I would love to see this forum in vBulletin. And I'm sure it would be fairly easy to convert, there are conversion engines for most forums to vB.
Advantages of vBulletin:
Most people are already familiar with VB
Easier for webmaster to admin - especially with mods
Just looking through the list of users here, I think you would have your pick of good mods
Disadvantages of vBulletin:
$85 a year.
But this could be recouped, if needed, through advertising (yuck) or a small user fee. Just 25 users at $3.99 would cover it. I for one would gladly pay $4 and I'm sure you could quickly find another 24. Especially if you offer something goofy like a gold border around their avatar and the ability to use the word "Geek" in their user title.