I just made a forum post on the creators.xna.com regarding the lack of a serializable attribute on the xna framework Color structure. A copy of the post is provided below. You can goto the actual form post by clicking here.

So I thought I would start a new project called XNAVisies and create a few simple debug visualizers for the xna framework objects. Hah!

Turns out I keep getting errors when I place a breakpoint in my code and bring up my debug visualizer for a xna color structure. I get vcexpress stating that Microsoft.Xna.Framework.Graphics.Color is not serializable!

A quick look at the xna assemblies using ildasm shows that almost all objects are marked as serializable like Viewports, predefined vertex structures like VertexPositionColor and VertexPositionColorTexture etc, also Ray, Matrix, Plane, Point, Rectangle, Quaterion,  and all vector structures are marked as serializable EXCEPT for the Microsoft.Xna.Framework.Graphics.Color structure! Which just so happens to be the object type I am trying to create a visualizer for! Gargh!

For all that is still sane in this world please microsoft, add the serializable attribute to the xna Color structure by the next release of the xna framework!.