Thanks for all the input regarding the colors. We won't be able to implement all of the recommendations because there will always be conflicting recommendations in a big group like this. When we first started, the colors were mostly black, white, and gray. Some complained and we changed to the orange and then some complained that they missed the neutral black and gray colors.
In this format we have many bright colors and also some neutral colors with the posts showing when you hit the 'active topics.'
The multi-color format will probably work because there will always be at least one color in the scheme that each of us likes.