Definitively a photo Best Viewed Large On Black.
Lighting: A Speedlite 550 EX placed to the right (outside of photo) was set to 1/4 manual output and pointed at a white wall 30 cm behind the marbles; triggered wirelessly. All indirect backlight, in other words.
Update: Wow, this has in very short time become my most favorited photo ever, and the only one to break top ten of Explore (reached #4). I guess sometimes simplicity is all it takes :-)