The above series of images goes as follows.

1.) An image setup with 1 light (shown where the white sphere is) and ambient lighting turned on. 2.) Same scene with ambient occlusion turned on. Looks sorta ok. The corners are darkened and there is darkness below the ball. 3.) Same scene as 2 but the only thing changed was indirect lighting changed to turn off ambient occlusion. Now it's too bright because not only is all the scattering being added but also the fake ambient lighting on top of that. 4.) Ambient lighting turned off (set to 0), indirect lighting turned up a little bit. Notice how the lighting is much more realistic. The shadows on the floor are correct as well as the scattering onto the blue sphere is also more natural. Lighting in the corners looks more natural and all the lighting behind the ball makes more sense.

-Kix