Nice picutre, but how did you do it?

As I said before, download this http://www.renderosity.com/mod/forumpro/media/folder_8/file_351683.jpg and change extension to zip, thats zipped blend file and see how it's done.
But in words, I have created ground plane in layer 1 and those cubes in layer 2. In layer 1 I've placed two spot lights at same place. First spot light has default light settings but the other is setted to iluminate only objects in the same layer (eg. that ground plane) and has intensity of light (energy) setted to 0.3.
In layer 2 I have placed one hemi light in exact oposite X and Y of those spot lights in layer 1 (just copy that second spot light that iluminates only things in same layer, change it's type to hemi and move it to layer 2. Change X and Y of that light to positive values).
Now spot light 1 iluminates all objects, spotlight 2 iluminates only groundplane and that hemi light iluminates only boxes but from behind (but note that hemi light is oriented at same direction as spot lights).

Well, I hope that this is helpfull to you...

Damir