As maya and other 3d software packages have more powerful options for lighting, it is getting available to achieve more realistic and believable lightings.
Folllowing images are inspired by http://3dluvr.com/pixho/ and http://www.cgrg.ohio-state.edu/~mlewis/Gauge/MapGen/map_gen.html.

Thanks to Matt Lewis, Emmanuel Campin, and Gye-do :)

I made a simple mel script to generate boxes randomly and started lighting based on Emmanuel Campin's domelighting idea.

lighting : 173 directional light with 173 d-maps.
s/w : Maya 3.0
 

lighting : 56 directional light with 56 d-maps.
s/w : Maya 3.0
 

After I rendered upper two images, I thought about what is making those image so look real. And my conclusion is "very soft shadows". So I made bottom images using
"area lights" and "very soft shadows".
One strong light has little bit high resolution d-map(256) and other two have less resolution d-maps(64). To have bouncing light, I add one ambient light with similler color of ground.

lighting : 3 area lights with 3 d-maps. one ambient light
s/w : Maya 3.0