I want to suggest to change the icon images of default icon set. They have little difference between each other. It is hard to tell what is what if just look at the image without point to it to see the title text.
I hope those icons can tell the visitor exactly what it means, and immediately. For example, a Question icon should be a Qestion mark as the main part; an Idea icon should use a Lamp image as the main part, etc.
Another example is the post icons of FireBoard forum component, which you are using on this forum. You can see that these icons are very easy to recognize.