@shadyJ if it’s going to make a significant difference I’d rather spend the extra money on 3 CCB-8. How do the CCB’s compete in this price range? Also, did you see my setup, is it terrible placing a center channel on the bottom?
I think the CCB-8 compete very well in this range. I review speakers for Audioholics, and I still remember the CCB-8 as having an uncanny imaging ability. There are some caveats though, it is a large speaker, and a lot of people don't like the way they look. Hsu has since added a model with a black cone, but I think the yellow cone version has more personality. Also, they are intended to be used at a slight angle, so they can sound a bit crisp with the speaker aimed right at you. If you decide to get them, follow Hsu's placement guidelines to get the best sound. They are also intended to be used with a sub, so they don't have much bass extension into subwoofer range frequencies, not that you need that extension if you are using them with a sub.
I think they would work better than normal center speakers in the cavity in your entertainment shelf. The reason is that they have relatively narrow dispersion on all axes, so they won't reflect as much sound in the vertical axis. Normal MTM center speakers actually tend to have a wide vertical dispersion, so they will be more prone to diffraction from nearby surfaces in a vertical angle, such as your floor. In other words, the floor will have a more damaging acoustic affect on a traditional center speaker than it would o a speaker like the CCB-8.