Get the new Silverlight Toolkit.
Be sure to check out the samples: Silverlight Toolkit controls sample, and Silverlight Toolkit Charting sample.
In this release, you get the following controls:
Take particular note of the new Data Visualization control, Chart, which is a free Microsoft charting solution for Silverlight that gives you:
SL Toolkit Chart sample
There are also some new themes to play with:
Now, go light up your web pages!