For anyone out there whose room acoustics suck and who either doesn't want to spend a ton on buying panels -- or whose SO doesn't want to look at a room full of Auralex -- I have an idea to share that worked amazingly well for me.
Instead of big bass trapping panels or expensive corner traps, I bought several stylish, loosely woven baskets with covers (Crate & Barrel -- $19 each) and filled each of them with three layers of 2-inch Roxul mineral wool insulation cut to fit tightly inside. I laid these side by side under my long horizontal TV/media table along the front wall, between my RTi10s.
Then I took Owens Corning 703 and used it to line the under sides of three side tables in the room (just cut it to fit very snugly and it should stay in place without having to glue it (I covered the exposed side with loose-woven cloth). Where possible, I used two layers to absorb more bass. None of this is visible unless you're laying on the floor looking up.
One of these tables is in a front corner above my subwoofer. That table has 4 inches of Roxul hidden on its underside.
And finally, I bought several cheap wooden boxes from a crafts store -- about two inches deep and about 1 foot long. I stained them and filled them with more Roxul and glued black cloth over the insulation (I bought black needlepoint cloth -- it's thick but loosely woven and very easy to work with). I tucked the edges neatly inside the boxes. These ended up looking kind of like speakers. I placed them randomly inside a bookcase, surrounded by books and other objects, along one wall to help absorb and diffuse excess reflections.
The result was phenomenal -- nearly invisible acoustical treatments (which pleases the girlfriend) and very effective bass trapping. My RTi10s, which I hadn't been very pleased with, now sound stunning with amazing imaging and very tight bass.
With a better-sounding room to work with, the Audyssey system on my Onkyo 805 was able to correct for any remaining problems, which has done wonders for movie sound effects, etc.
In all, I spent just over $100 to treat a room that's about 26X20X8 1/2.
Anyway -- since my girlfriend just looks at me and says, "That's nice, dear" when I tell her about all of this, I thought I'd share it with all of you. Hope it's helpful.