When I initially wrote the ASP.NET code completion, I added support for completing attribute values for enums and bools. More generalised completion using TypeConverter.GetStandardValues isn't so easy, since I don't want to load arbitrary types into the MD process, so I skipped this for now. However, I did special-case System.Drawing.Color, since it's used a lot.
This morning, on a suggestion from Aaron, I tweaked it to generate custom icons for each colour:

In other news, I landed the new ASP.NET completion parser, which is much more robust, and is also able to generate a tree, so it will soon replace the DOM parser too. The new design also means I'll be able to unify it with the XML and Moonlight (XAML) addins.
I recently returned from a family holiday in Maine, and will post photos when I got them sorted out and uploaded to Flickr.
Comments
Neat!
Though if you are going to live in the US, you have to use Color instead of Colour. :)
Consistency
I omit the "u" in public API for consistency with .NET, but it won't be easy (or possible?) to convince me to do that elsewhere :-p