Like Lazarus28, I too use Auralex with great results. I use the 4" Pyramids, Q-fusers and T-fusers (modified). The pyramids are gray and diffusers are painted the same color as the ceiling. Because the diffusers are supposed to be painted, you can match to your decor. Don't get the foam in anything but gray because the other colors are hideous. I really like Auralex products because they look good (once painted, etc) and they are inexpensive. Go to their website and look at the gallery, or better yet call them and get a catalog the pictures are better on hard copy. Finally, I have found that the best place to buy them is from
This place has the lowest price, fast shipping and great service (no, I dont work there or anything like that).