Gnome looks professional. Its free.

not all professional softwares are paid phpbb isn't paid right, .. due to that vbulletin is paid, some guys do faking on it.. as i mean on my post above here.. got more petitions that mybb will be free forever! lol i hope for vbulletin too

Have your guys ever tried Invision Power Board? Have more features, much more organised/advanced options avalaible in Admin ControlPanel, faster and have nicer smileys
Demo : free forums

@ Devinton: Yes I have tried using IPB but have little difficulty in organizing it properly

I don't know whether or not vbulletin is overrated but Mybb is really the best