I have two forums, each with over 1000 users (which isnt that big, but still...) and i dont think one of them has made a post saying: "Are you gonna upgrade to phpBB3!?!?"
I think I'm mostly upgrading because I love doing computer projects with forums, and I also love having a chance to mess some stuff up
What about you guys? Do you think your users care if you upgrade? If so, what do you think they're looking forward to most? I already know that my users will like the new subforum feature, because they have complained about that for ages...