Data Visualization Tools

1) Ruby -- for data munging;
2) Postgres -- for database management;
3) World Programming System (WPS) -- for SAS legacy data programming;
4) Tibco -- for data visualization;
5) R -- for predictive modeling/data mining.

The developing interface between Tibco and R is very promising. 

http://www.tableausoftware.com/ 
http://www.panopticon.com/ 
http://www.qlikview.com/us/explore/products

WEKA

http://www.gapminder.org/ 

http://projects.flowingdata.com/walmart/