I've always used vBulletin or some other forum software for creating a forum but now I have a WordPress site that has unique design and I don't want to break the consistency of the site. Therefore I need some forum functionality within WordPress. Have you tried any?
I agree with Anna that vBulletin is a much better option. I joined and is participating in several forums with various platform including vBulletin, SMF, phpBB and the platfrom for Wordpress. I love all the platforms except the last one.