Overview of the Rendering Process
This is a still from the final "SpaceCity" animation. The scene was completely done in Maya with compositing in After Effects.
The scene was modeled with Nurbs, only the "cars" and very few parts of the city are polygons.
Below are all the layers I usest to compose the shot together. Nothing special though, but I'd like to highlight a few things. All layers where rendered using the Maya renderer. I used render passes to get the firtst three layers, the rest was rendered seperately.

Diffuse Layer

Specular Layer: I gave this layer a little blur to simulate blowing metal

Shadow Layer: In the final composite I turned the shadows a little red...

Car Layer: rendered separately to give it a little more motionblur than the rest af the city

Sky: just the sky ;-)

Screens: whole city was rendered black and I used movies for the screens

Sun: This point was tracked in After Effects and a Lensflare was attached to it, to simulate the sun

Glows: All objetcs are black only the glowing objects are visible. Glow was turned off for rendering and was added in the Post using glow and blur effects. The glow in Maya tends to flicker.

Fog: Again everything was black so only the fog was visible

Diffuse Light: This layer was used to give the scene a little more depth. Below is an example with/without "diffuse lighting"
To render the "diffuse light" layer I used the "diffuse light" shader by Paul Carter which is available free on the internet. But be careful, the rendering times are extreme. To render the complete scene with fogs/glows/shadows just everything in full production quality takes about 15 minutes. And to render the diffuse layer in Low Quality can easily take 45 minutes, so be careful and start with a sphere ;-)