Building a house

In the design phase and planning on a dedicated listening room. Any advice on its construction, lessons learned?
It dawned on me that if you are setting up a permanent home-theater (i.e. will always be in same location), you should probably put some electrical outlets in the floor where your seating will be. Modern HT chairs have USB outlets, motors and regular outlets built in. and you don't want wires to trip over if you plug them into wall outlets.
I thought about my house not so long ago, now people are working on plans, and I wanted to do the design already. Additional noise reduction, I wanted a panoramic window, but I realized it was stupid. Plus the cabinet layout. 

About 15 months ago we moved into our "forever home", with bonus room above the garage, which my developer was willing to customize (to an extent).  Besides having them move an interior wall from the typical design (giving me 19+' of wall for the components), I had them upgrade the carpet and padding, had them do a CAT6 run and dedicated 4 outlet grounded 20amp electrical run.  Not only is this a great sounding room, when I'm playing my music loud, my wife is not at all disturbed watching TV down in the living room!