I think the biggest issue for this site is the main page and I think it should play to the forum's greatest strength: photography.
I think archBoston.com could easily be the premiere Boston-based urban photo site. Just setting up something simple like a
tumblr on the front page would bring tons of visitors to the site. You could leave submission open and whoever uploads whatever and just selectively edit from there. Another option would be to select photos from the Photo of the Day thread.
Just some thoughts.
Edit: As far as the forum goes, it's fine the way it is. All I want are a strike out tag and a spoiler tag.