Hash Tagging plugin:
http://www.vbulletin.org/forum/showthread.php?t=269060
Adds a tagging system like twitter's that parses hash tags and adds them to the cloud. So instead of tagging threads in the box down below that almost nobody ever uses they could just say #texttourney or #BeastMode or w/e
Global Threads:
http://www.vbulletin.org/forum/showthread.php?t=258109
Makes it so you can make threads that appear in every board so that people can respond to them as opposed to the Announcements which seem to get ignored or spawn other threads about the same subject.
Embed Google Docs:
http://www.vbulletin.org/forum/showthread.php?t=250782
It'd be useful for us
Mark Thread as [Solved]:
http://www.vbulletin.org/forum/showthread.php?t=211020
Does just what the title says. This would be useful in the help boards so that resolved problems can be marked as such.
LiveTopic:
http://www.vbulletin.org/forum/showthread.php?t=201228
Basically makes it so that if you're in a thread you don't have to refresh to see new posts. Looks pretty cool to me.