Originally posted by coolqf
The optimal angle for the rear speakers is 30 degrees back if starting horizontally from your shoulders.
For the front speakers, 45 degrees from the shoulders is best, and of course 90 degrees for the center speakers.
Actually, acording to Dolby labs, IIRC, the best is 90 degrees (on your side) with about 2-5 feet above your ear-level.

I have mine set at about 2-3 feet.

This helps the sound envelope you while watching movies.