Re: Theme

Using drupal forums isn't bad idea. people are doing and I can say - really successfully. Of course you don't get such functionality as phpBB or vBulletin, but it is more than enough to make discussions. More functionality can be achieved with various modules like private messaging, attaching, moderation, permissions, and so on.
I like the idea of using single user account for site and forum. Easy to maintain - and it has good SEO.
Of course it could get better probably it will in future releases.