here's a quick variant to the image after being rendered out in layers and photoshop'ed. Immediately it lets you play with the effects and help spot those problem areas

Jay: That building with the shadow/spec issue is still a default lambert shader whereas the rest have a generic shader on so that might be causing the problem.

I'm still not sure about what effects to use for each layer but this is what the following image has (as an experiment):

specular - color dodge
diffuse - soft light
ambient occlusion - normal
background - normal



Si