Sony's new flagship Theater Quad 16 Channel Dolby Atmos/DTS:X wireless audio system would be a very good choice for your room.
Yes, a dedicated audio receiver and wired speakers if properly selected and professionally installed can be designed to deliver moderately better audio performance...
Nick, just send you a few questions on another PM. Please answer when your time permits so I can complete the best equipment to best match your interests and use-case.
I'll make some projector, motorized and manual drop down projection screens and audio recommendation tomorrow.
For now I'd like you to know that if you just paint the ceiling and left/right wall in front of where the projection screen will be located (in front of the windows with flat black or...