I kind of like dark themes with light text. I don't know why really. I always liked gaming sites that have a dark background, I think it's the overall effect though, when done right with colourful graphics accompanying it, then they can look quite nice.
I have a site that is grey behind with light writing, sometimes people complain and even I am tiring of it now - I think I might go to dark on white with that one.
The thing about dark sites is I think they kind of close you in a little more, everything seems a bit more concentrated if that makes sense. And with a gaming site a lot of what you are after is atmosphere, so that's my theory as to why they work in that situation.
Interesting stuff, thanks for posting