I am a fan of "less is more" and I personally try to keep it simple
and professional. That is why I am not a fan of background images.
It is different if you run a design website or a professional business
website. I think a background image would be to much.
The welcome box is "in your face", I know but that is exactly like I want it.
I want people to register and not to keep them lurking.
I maybe change my mind later but right now I like it.
Regarding the navigation, I don't really get what you mean by that?
The forum navigation contains all the important links.
And I don't want to link inside my content from the navbar.
I don't use blogs, don't offer video uploads or such.