What do you think is the best forum software? My personal favorite is IP.B (which is however too darn expensive). Second to that is phpBB, but Mybb with themes is awesome too.
For paid software, I'd say IPB and Xenforo. Definitely not vBulliten haha.
For free software, I'd say MyBB.
vBulletin is... terrible. SMF seems old and clunky in a way. I like phpBB because it's more modern. myBB out of the box is terrible, but with themes, it's a whole different story. IP.B is expensive, but awesome.
SMF is leaps and bounds ahead of vBulliten, especially considering the recent vBulliten releases. SMF can be a pain to use in some areas, but it has a lot of really nice features as well, so I like it.
myBB is still better in most areas though, as far as free software is concerned.
Desker Suite (even though it's not complete).
It's going to be a free alternative to IPB or vB, but with less clutter than vB, and not ridiculously expensive like IPB.