Microsoft has recently released a ASP.NET charting control for .NET Framework 3.5 SP1. The good thing about this control is, it is FREE. Once installed it can be easily used as a Server control like any other Microsoft controls. It supports a wide variety of charts like, Pie, Area, Doughnut, Point, Range , Circular, Accumulation, Data Distribution, Price Change and Advanced Financial Charts. Once you install the working sample, you will get a feel of all above mentioned chart types. The sample project includes almost 200 pages with various chart types.
As far as the data, either you can specify the data while declaring the control on the HTML or you can dynamically assign the data on the code behind using the data binding techniques. At runtime charting engine renders the chart as a PNG image and it is referenced from the HTML using the <img> tag. If you want to make it interactive, use these chart control in combination with AJAX. You will also find some samples around the interactive charts using AJAX in the samples projects.
You can use following links to learn and download,
If you have any question don't forget to visit the Chart Control Forum.
To give an idea of how these controls looks i have attached few snapshots from the samples project.
Have Fun with the Free chart controls and Good luck.