I am have an electrician pull (3) circuits into my "media room", a 20amp for my Bryston 28BSST, a 15amp for the rest of the audio set up and a 15amp for the HT set up...Just my 2 cents, use the same wire gauge for all three dedicated circuits. If less than a 50' run, all three circuits #12 awg. Have him keep them pretty close to the same length if the equipment connected to the three dedicated branch circuits will be connected together by ics. All lessons the chance of ground loop hum problems.
Wire? NM-B cable. (Romex brand is an example of NM-B)
Rough in boxes? Plastic.
Breakers? 20 amp.
Install all three dedicated circuits on the same Line in the panel.