Okay, from my honest opinion, the start page looks pretty good. And well done for not using a flash animation for the buttons, as now search engines can easier index the content such as the forum.
Forum looks pretty stylish, buttons and colours seem to go well. Probably too many forums, and certainly some empty ones, so try and fill them with posts and content to make the site look more active.
vB code selection looks quite plain, and you may want to add some custom BB code (thankfully it's easy to find, as even I myself released some recently). Smilies look pretty good, such as this one:
I don't know what you added other than the smilies and arcade though, because a lot of pages are members only to view (such as profiles). So I can't give any suggestions there.
Okay, so I see you added some avatars. Nice I guess.