Your header is very nice, but those navbar buttons look very out of place. I don't know what effect you wanted there, but it isn't working. =/
I also don't see the point of having 'Latest Topics' ON the forumhome page. On a portal, yeah, but when they're on the forum, all they have to do is click on 'View New Posts' and that page is individualised from their last visit. A much more useable feature there. To me, it just takes up too much room. =/
Otherwise very nice. Like your images.