Saw the new (?) chart API  yesterday and so far I am impressed with the amount of options you have when you generate charts. For the moment the only limitation is that you're limited to 50k requests per day, but that should be enough for most uses (esp. when you use some smart caching).

To make using the API just a bit easier I started with a wrapper in C#; for now it only supports the most basic options for the 2D and the 3D piecharts, but the more to come soon.

If anybody is interested in helping complete the wrapper, let me know and I'll host the source on CodePlex.