I own an Onkyo 805, and I say you stay with that. You have a big room and you will need all that power to pressurize the room. My room is 12' x 26', and I have wall mounted Maggies, and 2 subwoofers (2 subs would be highly recommended, buy one now and add another later.) I recommend Maggies, (but not the wall mounted ones, because your room is too wide), but that is a personal preference. Find a Magnepan dealer, and give them a listen, for a lot of people their speaker auditions end there. Have fun!