Equi Tech makes a high grade subpanel that creates balanced power for all breakers right at the panel. They are usually used in high-end recording studios, but if you want to go all-out, and price is no object then they are the real deal. If I ever get to build a dream theater for myself or someone else then that would be my choice for the theater subpanel.
The above suggestions for grounding from other posters are excellent. There is also some great info on the Equi Tech website about optimum grounding procedures, some of which I will soon follow in my showroom theater.
Basic city electrical codes only require a minimum grounding effort. If you want better, which will greatly help your system then you have to do it yourself or pay an electrician. They may seem expensive, but they are worth it because they know what they are doing and know how to NOT get fried. Some of them will tell you that your extra grounding efforts are unnecessary because they don't really get what you are trying to do. On some of my theaters I have had to finally tell them to just do as I say, even though they don't grok the benefits. Then when they hear the theater and their jaw drops open they finally get it.
Good luck with it all, and don't forget to take extra caution with anything electrical.
