If the house is being built you have a chance to avoid all the mistakes I see in your drawing.

Seriously, first get that furniture out of the corners. You'll harm the acoustics much less if you put them along the side walls behind your seating. Then center the TV and speakers left-right in the room for proper symmetry. If this were my room I'd put the sub in one of the front corners. Is either wall an outside wall with insulation inside the wall? If so, that's probably the better corner to place the sub. I'd also avoid wireless speakers if possible. Just one more thing to go wrong.
More here:
How to set up a room
This short article is mainly about home recording, but all the same principles apply to hi-fi and home theater too:
Acoustic Basics
--Ethan