Atangeo Team recently released Balancer 1.0,
which allows quickly and easily simplify 3D models.
It also features fast and effective triangle reordering to
speed up rendering by optimal utilization of GPU vertex cache.
Hope you will find Balancer useful.

From the press release:

Atangeo Balancer is a tool to optimize and simplify 3D models.

Its exceptional performance and a novel user interface allow finding
perfect balance between visual appearance and the number of polygons,
quickly and easily. Balancer utilizes a high quality polygon reduction
(aka mesh simplification or decimation) to preserve the visual
appearance of your model. The model features, normals, texture
coordinates, layer boundaries are all honored by Balancer. It can
optimize your models even further to dramatically speed up rendering
of your models. Balancer features a fast and efficient triangle
reordering that can be tuned for various rendering methods like
triangle strips and array/buffer based rendering.

Balancer Lite is a free version. It is fully functional but works with
small meshes only.
The limits for a single mesh are 15000 triangles and 10000 vertices.

http://www.atangeo.com/

Upon your fair requests,
we've put some nice examples and screenshots of some pretty complex models.
Please take a look.

Balancer was updated to version 1.0.2.

Here is the list of main improvements:
- Full support for smoothing groups
- Intelligent vertex joining
- Enable/disable lighting for easier silhouette inspection

Thanks to everybody for contributing ideas and requests.

Download link: http://www.atangeo.com/download

And there I was,looking through the DirecX SDK, in the examples, to do the same sort of rendering performance optimizations that your program provides. Your solution by doing the changes on the model directly, rather than doing it after the model is loaded is a much more elegant solution for me.

Thanks for providing the Balancer Light for people to play with.

Great ratio price/performance. Probably one of the best decimators on the market for almost no money. Good support too.