Hi Glowplug, I don't suppose you could find a room that isn't essentially square to use? Imho, get Echobusters "Cornerbusters" to treat the midrange megaphone effect. Try to change the dimensions of the room by filling up one of the walls using things like bookcases filled with books, wall-mounted shelves (dirt cheap @ IKEA if you have one nearby,) etc., anything to reduce the symmetry of the room.
Don't do the setup with the subwoofer hooked up; add it later - if you must use it in there. Your B'mers actually have an astonishing amount of low end heft if you set 'em up correctly - I owned those myself and can vouch for them.
You're trying to do too many things in that tiny room: storage, workspace, astronomy, music listening & playing. Pair down the number of functions.
Get a more comfortable, shorter listening chair.
Lose the desk and put all your radio gear (or whatever that stuff on the desk is) up on wall shelves or in bookcases. Take the doors off the closet and store them elsewhere - if aesthetics are a prime concern then put up a shower rod and some drapes to hide the clothes. Lose the equipment rack. Put all of your equipment on 18" stone tiles (or very short stands) on the floor.
Another thing I'd try if that were my room is to change the orientation of the speakers & listening position to an asymmetrical arrangement by pivoting on the right speaker's axis about 30 degrees to eliminate all or most of the flutter echoing & change the resonant characteristics.
As far as equipment goes...
I've found Rotel to be quite dull & grainy (I have an RB 1080 200w x2 and a 930AX integrated) I'd recommend you check out the NAD C 316BEE integrated for $349 it's grain free, musical, smooth & pretty noise free. I also have an inexpensive Sony BluRay player that works pretty decently.
Well, you did ask for suggestions.
