OK, let me just tell you, that against, phpBB or MyBB, they both beat SMF. Know you might say why? SMF has more plugins than MyBB, but less than phpBB.
That's a bad sign, as SMF lacks many features that phpBB and MyBB provide.
phpBB has more plugins/mods than phpBB, but they add features that NO forum will provide.
Now MyBB is so much more user friendly, and it is SO easy to style it, OMG.

Please consider one of these alternatives;

Thanks,
-Alex

EDIT: I also have a vBulletin license that I'm not using. It expires July 2008.