I too use a similar setup with an Emotiva UMC-1, QSC RMX 1450, Mirage Omni 550s and a Pinnacle Baby Boomer. To be quite honest, a few of the decisions were based on emotion, others on what was cheap or what I already had. I love the setup though, it sounds great and gets louder than my room can handle while staying very clean.
Edit: Can't leave out the RasPi running volumio.