Vbulletin is hella great. I think that'd be very possible to get here, too; I visit a forum much less active or popular than this, ran by one guy right out of college, and he's willing to pay for the license out of his own pocket. I think if a monthly forum fund was taken up to ease the cost, it'd totally work. Not that SMF is terrible, though. Anything with avatars will be great.
Also, devs? Let's, um, go in a different direction with the forum skin this time (to put it politely).
EDIT: Also, I don't guess it would be possible to move all the forum history over there, would it? I think that works in boards using the same software, but I wanted to double-check as to boards with different software.