Just a quick plug then for my own project: https://github.com/grokys/Perspex/

And WPF seems pretty slick. I've only used it as a developer who has little UI skill, but it seemed to be far better than other UI kits. The design seemed rather coherent. Too bad performance and rendering issues hurt it for the first half decade of its life.

Unfortunately, I think a lot of the interesting parts of WPF are just wrappers around DirectX APIs.

That's just for rendering. All the controls and data-binding mechanisms are straight-up C#.

For example: http://referencesource.microsoft.com/#PresentationFramework/...