I have a side project in which I implement a model of load-propagation through a structure. Then I use a genetic algorithm to find structures which are stable and which satisfy other criteria. It's too involved to discuss here, but here's a screen shot from an early version. 

Screenshot 

Early version of the EvolvedStructures 3D visualizer.

What's important for this discussion is that I use Managed DirectX to render these structures. The unmanaged DirectX API is a harsh mistress, but the managed wrappers are much nicer.

When the MDX 2.0 Beta came out, I dutifully ported my code from MDX 1.1. This required a fair amount of refactoring, but the new framework was even nicer than 1.1, so I bit the bullet and trudged though. 

Imagine my dismay when I went to install the October 2006 DirectX SDK and I read this:

Managed DirectX 2.0 Beta Removed

In the October 2006 SDK, the Managed DirectX 2.0 Beta has been removed and is no longer supported. There are two distinct paths for developers migrating from Managed DirectX 2.0.

If you are currently using Managed DirectX 2.0 for tool, editors, or other applications that require specific Direct3D, Direct3DX, DirectSound, or DirectInput functionality, you should migrate to the Managed DirectX 1.1 runtime. Managed DirectX 1.1 is completely compatible with the .NET Framework 2.0 and will not require you to change the version of the CLR.

If you are planning to release a game using the .NET Framework, it is recommended that you adopt XNA Game Studio Express, currently in beta. XNA Game Studio Express uses the XNA Framework which is very similar to Manged DirectX in many respects. XNA Game Studio Express is scheduled for release before the end of 2006. This first release is targeted at hobbyists developers and students.

If you have any questions, comments, and/or concerns please contact xna@microsoft.com

Swell. I can either back out all my considerable changes in the port from 1.1 to 2.0 Beta, or I can adopt an entirely new platform, or I can use WPF.

Hmm, tough choice. Fortunately, I have only the one app to deal with. It would be kind of cool to migrate to an app model which runs on XBox 360. See, I have this idea for a game...but that's for another time.

I'll keep you in the loop when I decide what to do.