Strictly speaking, being pretty is not the most important aspect of a charting applet, but with me it ranks quite high. No matter how advanced the code behind it, if the charts look rough, unfinished and downright ugly, there’s no way I would use them in an application or on a site. It’s a relief to have both feature rich and beautiful charts to work with.
Meet amCharts from Lithuania. I’ve been mostly using their Flash charts, but they also have .Net, Flex and WPF & Silverlight versions. Very easy to use, too 
There’s a settings file which allows complete customization of all the chart details and there’s the data file in XML or CSV format. That’s it – with a few lines of code your data will be displayed in a very pretty and interactive chart
The best thing is it’s all completely free if you don’t mind the link to their site in the upper left corner If you do, I’m sure they’ll welcome another paying customer. They surely deserve your support for all the work they’re putting into the product.
