I went down the 10/3 Romex route, std 15amp breakers. You can get special audio grade wire, which I am sure gets expensive quick. I did two circuits (I am using a stereo amp). This made a very significant improvement, very cost effective at around $1.5K. Later I upgraded from the hospital grade receptacles to Isotek and got another very cost effective improvement (~$400).
I would think this would be a basic approach. If your system is or will be very good and you can afford it, it would be justified in going further.