Data mining? look into R. It’s open source visualization software.
As ReadWriteWeb notes:
The New York Times graphics department has long used R for its data visualization features. R is often used for interactive graphics that reveal patterns, provide context and describe relationships in visual form. The R-based graphics span all departments — from breaking news (the destruction of the Haiti earthquake) to politics (the 2010 U.S. election) to entertainment (Netflix rental habits) to sports (a breakdown of New York Yankees’ player Mariano Rivera’s pitch chart).
Amanda Cox of the New York Times’ graphics department says, “R makes it easy to read data, generate lines and points, and place them where you want them. It’s flexible and quick - which is helpful when you’ve only got two or three hours until deadline.”