Cytoscape
Cytoscape is an open source tool for complex network analysis and visualization. Additional features are available as plugins.
Price: Free...
Maltego
Maltego is an open source intelligence and forensics application. It allows for the mining and gathering of information as well as the visual...
TouchGraph
TouchGraph is an on-line network visualizing tool that provides a hands-on way to visualize networks of interrelated information. Networks are...