Render settings: I generally use my number 3 preset: "Fast RT" for shader and light testing scenes like this, settings as shown.

Lights:

The most important point to note for the lighting setup is that I am using gamma correction. If you don't have Poser Pro, you will need to do this in your material shaders.

Normally for testing I would use only one IBL and one infinite. However, I left a third light switched on by mistake.

Diffuse IBL for general ambient light - white, intensity 40%, which seems very high but I use a fairly dark image "Attic.jpg" that comes with Poser. I like this IBL image and use it nearly all the time because it has good directional contrast without very strong colours. IBL contrast is set to 1.0 (in the Material Room). The default is 3.0, and this is too high - it creates too fast a transition from light to shadow. I have AO switched on in this light, strength 0.5, bias 0.03 (these surfaces are nice and flat, so a low value is possible without artifacts from bump etc), max distance 36inches, samples 8. With higher intensity on the IBL, I found I need to turn down the AO strength, or decrease the max distance, otherwise it becomes too strong. These days I'm tending to use material-based AO in my proper renders, but IBL AO is convenient and good enough for test scenes.

Infinite light: white diffuse+specular at 20% intensity, raytrace shadows with 2.5 blur radius, positioned behind, above and left of the camera.

(Normally I would have the IBL at lower intensity (10 to 20%) and the infinite higher, but I wanted brighter all round lighting in this case.)

The third light that I meant to switch off is a point light positioned between and just above the spheres. It has bagginsbill's inverse square falloff shader in it, which combines an intensity value with a distance from the light at which this intensity occurs. Mine is set to 200% at 72 inches. The intensity at the actual light source itself is in theory infinitely high. Its full effect is not seen here as the other lighting drowns it out rather.

The floor and wall are both procedural shaders by bagginsbill. The funky one on the wall is actually one of his Orb shaders!

Well... I hope these are useful details. I'm going to bed now, but I'll answer anything else you want to know tomorrow. Nite nite!

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)