Visualizing data must be based on understandable data values, understandable metadata, understandable terms, and understandable meanings, all in a given context.  Without this structure, any data visualized by the excellent tools you cite would be "meaningless" or "out of context".

A terminology shared by the intended audience of the data visualization technology would be needed to make the data understandable across that audience.

Adobe Flex can provide some good out of the box visualization technologies for the web environment. However, we've built several flash/flex-based visualzation engines and there can be tremendous limitations and performance issues - especially if you're dealing with large databases driving the visualization engine. I recommend Ajax-based componentry as it provides better optimization potential and better ability to integrate with other "mashup" components.