We use http://amcharts.com/ http://amcharts.com/. The thing I like the best about it is that you can customize everything through a visual web based editor, an

We use http://amcharts.com/ http://amcharts.com/. The thing I like the best about it is that you can customize everything through a visual web based editor, and then just copy the xml that is generated. It has also been stable for us, but one downside of course is that the web browser needs flash installed.