Invision Power Board is another to consider.
http://www.invisionpower.com/community/board/index.html
In particular, check out the new IPB version 3 preview...
http://ipb3preview.ipslink.com/
Personally, I prefer vBulletin, but you may find IPB has some features / looks that better fit your needs.
If in doubt, go with vBulletin - time proven software with excellent support.
http://www.vbulletin.com/
Ron