I have been told that when you use Quietrock of any of these other sound deading materials, you want to minimize the amount of wall penatrations.... My question is what do you do about you AV wires? Do you put it in an electrical box with quiet puddy? What are the best practices? I have a home theater that will have both a drop down screen and projector, as well as a plasma up front.... So, I am trying to find out what to do about the Component & HDMI cables for both plasma and projector...

A lot of guys build boxes out of mdf that get mounted to the wall and then have the electrical box mounted inside the mdf box. That way you only have to seal where the wire enters the mdf box (assuming you have sealed your mdf box by covering most of it with drywall and chaulking it if necessary).

You can also use putty pads as you suggested in your original post. The extreme approach is to put the low voltage (and high voltage) boxes in columns or soffits so you have an extra layer of drywall stopping sound waves (of course, caulking the exit point in the main wall while you are at it). I've seen a few posts from others referencing test data that outlet boxes themselves are not really something to worry about all that much as long as the holes within are caulked and you caulk any gaps between the box and the wall itself...the key is acoustical caulk or some other caulk that remains flexible.