i have 2 krell amps 250w per channel @ 8ohm, total of 5 channels. and my ep600 as well as the tv and dvd player, and cable box. i have m60's, QS8's and a vp150. my room is about 20X15X10 and opens into the kitchen as well... all on 1 15amp breaker.I have never poped the breaker, what kind of amps are you using? How loud do you play your music/movies? when we are watching a movie you can hear the ep600 pretty well outside the house, depending on the movie. depending on the price, you could put your amp on a dedicated breaker.
I didn't see you listing what kind of amps, or receiver you have. if you have a receiver, and do not plan on upgrading to pre/pro i would not worry about dedicated breakers.
one thing i would tell you, if your getting a new house built, ask for the wiring per schematic, and make the builder give you the schematic. i was talking to an electrician, when i had some work done a few months back and as we were talking, he said that the new builders were running 12 gage to about 6" away from outlets, then finishing the run with 14 gauge.... make sure you get what you are paying for, and hold the builder accountable, and make them prove it to you.
if your worried about picking up noise on the speaker wire, i would not worry about it. if you run 12 gauge you'll be fine,
putting everything on different breakers will not make your system sound better. you just need to do the math like others have stated to make sure that your components are not going to draw more power than the breaker your thinking about putting in.
if you want to spend the money for isolation transformers and capacitors ect, to ensure the power to your stereo is better than what your pulling off of the grid, sure you can do that, but i think that will get into way more money than most of us are willing to send.
Good luck with your decision.
