vBulletin is an OK board but it has some major glitches that make it... well... not to bash... suck.
There are problems with recognition of read/unread topics that make it really un-fun to use. I know it's that you probably won't switch now (considering you've paid a license fee for vBulletin) but if there is a chance... phpBB3 and IP.Board are both waaay better.
https://www.invisionpower.com/
http://www.phpbb.com/ - Free!