I prefer splayed wood panels for walls and some splaying on the ceiling. I have also heard good results with adjustable hinged panels on the walls instead of splaying. I wouldn't spend too much up front on acoustic treatments because you need to consider the room as a component of your system. Since the room is the most tuneable component, you should spend most of your time afterwards and tune the room to integrate best with the other components. I prefer relatively inexpensive hospital grade power conditioning to any audiophile conditioners. These completely regenerate your power to make up for any bad power coming into your house.
New Dedicated Audio Room
I am in the initial stages of buying and building a new home. This home is going to have a dedicated audio room. (Approx 18'x 26') I will be working with the builders regarding the room and want to hear some suggestions regarding sonic improvements. I plan on using Hubbell outlets with 4 dedicated AC lines. I am also going to have the builders use thicker sheet rock for the walls and ceilings. Any other suggestions??