Square room, bass nodes are going to be bad. Be prepared to employ active bass equalization and or room good acoustic treatments.
Will you be listening at all to music?
I'm a big fan of Martin Logan, they have some on-wall and in-wall products too.
MartinLogan | Premium Speakers for Home Theater & Stereo
The Definitive Technology - Mythos series gets big points on Industrial Design, but I have not heard them, only seen them at Best Buy.
Definitive Technology - On-Wall Systems