room shape and speakers?

Whats the best room shape for speakers? Would a square room be the worst because of equal reflections? Also I visited a music
room where the speakers were positioned downward from the ceiling to the listener.(Very tall ceilings compared to length/width) Is this a good idea?
No, square is bad for acoustics since all the modes (which create emphasis and nulls) would be equal and additive.

No, aside from Fiddler on the Roof, it would be an unnatural perspective.