Good Q, I've been waiting for this topic to come up.
(and altho it *is* your world and I support 100% whatever you do, I also appreciate you asking us..)
Now then, I vote for upgrade, fresh start, with 'important' stuff archived.
Upgrading i think is inevitable at some point anyways, so why not do it relatively soon, once you/we've got the decisions sorted out and you've got the time to devote to the initial process.
Regarding the 'feel' of the current forum, I would suggest (altho this may add to the 'pain in the ass' factor), is to incorporate/transfer as much of the current 'style' into the new one, so people still feel like it's 'comfortable, home'.
I think the new features avail in the new vB will in the long run, be an improvement, administratively and as a user. Features that people may want could be more likely in vB3. (Altho I recommend in general keeping out as much 'fluff' as possible. People want things to be relatively simple, yet usable in the ways they want to use them).
Anyways, them's my 2¢.
