Which is the best acoustic/soundproofing wall covering?

You will get better performance for about the same cost if you use this entry level room analyzer:

http://www.hometheaterhifi.com/volume_9_4/cara-sof...

I think they offer a free trial too!

After following the steps in the software you will find that a few strategically placed absorbsion and dispersion panels will work best. I buy from Quest Acoustical Interiors due to their excellent performance, but they seem to be reasonably priced too.

http://www.questai.com/products.php

For sound proofing, these guys have affordable options that work reasonably well.

http://www.tectum.com/

You really want a "Dead room" for theater? Its usually best just to use a combination of floor carpeting and heavy curtain material, where needed, to soften any areas that encourage standing waves, or hard reflections. Overstuffed furniture, properly placed, can be used also. If you really want to make a recording / anechoic chamber out of your listening room, just tile it with standard asbestos acoustical tile squares. The little white ones with all the holes in. Your room will be so dead, it will assault your ears when you enter it. My be is. though, you will find the experience very disappointing, and rue the day, I would try to find a place set up like that and hear what your getting into first.

fir out sheets of peg board, the sounds goes in but cant get out