I put in a 100A sub panel into the media room. Not because I felt I needed it but because 1) I wanted the ground runs for all the circuits to be as short as possible and 2) have more circuits than I could possibly need for flexibility. If I decked out the room, the max power demand would be over 10,000watts of amplification. I’m fairly sure that continuously I’d never exceed 5 to 10% of that. 15 to 20Amps would still be plenty.