Ozzy, Live end/dead end is a credible notion for set up. Speakers on dead end. listeners chair on live end. This has been around for years. Obviously how well it works depends on your room and how its executed.
For OP, if you feel you must, I'd recommend diffusors on the wall behind you, but personally I think your CD storage if they are spaced irregularly would be better than a flat surface and all you need unless you are pretty anal. Spend some time with experiments and see what you can actually hear as opposed to 'theories'. For example take down your CD's, what to your hear? Place a heavy wool blanket on the wall, what do you hear? As Ozzy suggested, think live end/dead end and experiment with deadening some, or a lot, of the rear and side walls relative to speaker placement. FWIW I use room furnishings to solve reflection problems not only because they look better (to me of course) but they make reflections less uniform, which I think is good, but I realize others may disagree and want to have identical reflections thinking that they will increase depth of image, etc. That said, speaker and chair set up can go a long way in solving a lot of 'room' issues. For example, bass issues, I see folks trying to kill excess bass with corner traps when the problem is that the listener chair is in a bass node and all they have to do is move the chair a tad (out of the node) or that they measure bass in the corners where it always dwells and conclude that by killing this bass (which they can't do by using domestic bass traps). I guess the message is to solve actual, extant, problems, not theoretical ones. Have fun but take your time. :-)
