Here is where I am at now with this project started in August 2010.
Using a Cube Fill light resized to cover all the buildings, with 64 lights, shadow Bias at -25 (thx Rashad for that tip) Shadows at 70%. Sun at 160% Spec at 70%. No sun soft shadows used as the render time would have been a week or so. LOL Render Quality was set the Regular as I found it too grainy when rendered without AA. Played about the FOV to lessen the fish eye distortion that occurs on the edges. I think I set the FOV at 100 at 120%. The Planets were rendered separately and a mask rendered with it.
To be honest I am still not 100% happy with the lighting.
After I had rendered all the elements and masks I then put it all together in PSE and gave it a few post processing functions like Sharpness and a soft orange tint. Gave the Dome a Bevel as I rendered a separate mask of that too, just in case. I even render the clouds and sky in a separate layer and making the clouds colour colour white and turning off the atmosphere and making it all black I made a mask of the clouds so they could be placed on top of the planets. Obviously I had to render a mask of the city to bring that forward making it the top layer in PSE.