I think you've got something nice here. I personally don't care for the color scheme or the letter-based voting, but as you mentioned your likely user base will be comfortable with that. Probably a good move.
I'd actually use more line spacing between news stories though. It feels a bit too cramped to me. I agree with other comments about the ads too--lose them for now.
thanks very much for the feedback! it has been an interesting exercise for us: balancing what users what, what users actually DO on the site, and "good" design all at the same time. We've ended up going after the first two more aggressively at the cost of the third...simply because good design alone in a forest is worthless :)
I'd actually use more line spacing between news stories though. It feels a bit too cramped to me. I agree with other comments about the ads too--lose them for now.