I encountered this cool and powerful tool called Highcharts, which uses jquery to create interactive data visualization. The benefits of using jquery are 1) it works perfectly in environments without Flash (e.g. iPad, iPhone), and 2) it's HTML 5 compatible. The tool is free for non-commercial use.
Two demos below.
1) You can supply data (e.g. such as from a static spreadsheet file, dynamic JSON data from server, or even an HTML table) and customize the type, appearance, and interactivity of the chart. You can put multiple graph types in a single chart. And you can even print the chart or download as images/PDF.
2) It's possible to allow the user to interact with data source.
I just love it.