Uh, why are you telling us the texture settings of the plane’s material, if it’s just plain white?? That is, if there’s no texture channel and turned on, those settings are useless… and if you want a plain white material, what are you texturing?
The sphere looks more hemispherical, bisecting the plane… are we talking about radiosity here? The “bare white” tactic? Because your cube stack looks illuminated harshly, some of the front shadows are nearly black.
For your white color plane & sphere, did you push it’s reflectivity up to 1.0? IF not, it will appear gray unless you really saturate the lighting which will in turn blow out the highlights of everything else.
Setting alpha lower for the floor?! That will make it translucent, and let the background (which I assume is white) show through, is that what you’re hoping?
There’s a few different approaches to this, but yours is … well, different.
Have you tried GI or AO or radiosity any?