Yeah, we use Vbulletin 3.5 here, its _reasonably_ priced. You can also check out Invision Board which is a bit cheaper i believe, or PHPBB which is free
There are loads of others out there, but those are the ones i've used in the past.
I personally like phpBB, as it's easier to use for the users than SMF (the quotes feature has never worked correctly on any smf boards I go to). If you've got the money, vBulletin is great. Invision Power Boards I dislike the layout of, and the fact they now make you pay for a piece of software that isn't worth it
If you use phpBB, and need any help, I'm pretty good with it now
ive always used PHPBB, theres one reason for this... its FREE!! and its pretty decent aswell i used to really like it until i joined HEXUS which uses VB and its the same here . VB is definetly one of the nicest forum packages you can get.