I agree on the forum width. There is a large left and right margin on my 1280x1024 display. I'd estimate that they take up about 37.5% of the width of my screen, combined. I've looked for a forum preference to change that, to no avail.
Chat? Meh. I'm not much of a chatter. I imagine some would greatly like it, though.
Contests, for me, seem good because of the fact that they encourage users to get something done
I think that we'd see more examples of what Construct can do, with contests. Thumbs up to that.