You might want to look into this website:

www.gikacoustics.com

I'm forgetting which board, I think it was at the Tape Op board, but the owner of this company and Ethan Winer, the owner of Realtraps, have both been supporting each other's product as they each target a different frequency range. The GIK panels also seem to be getting some good user reviews.

I don't have the room yet to build in, but when I do, I think I've narrowed down my acoustic panel choices to these two companies. My current idea is two of the GIK panels at the first reflection points on the side walls, a couple of Realtraps for the corners, and probably some bookshelves across the back wall for some diffusion. Of course, this is theoretical, but it comes from trying to decipher the acoustical articles that I've read. I also recommend reading the articles at realtraps.com for other acoustical tips.

Good luck and let us know how it works out.