I just would like to announce that I've released Datagr4m, a framework dealing with graph visualization. Why another one? It let you build hierarchical clusters of nodes in a graph, which makes the layout more readable than standard graph layouts. It has other advantages that you can read/see here [1].
Despite the .com domain, all is open source [2]
There is also a Neo4j viewer application to let you navigate a hierarchical graph [3] and some standalone demos. A few videos give an overview of navigating computer networks graphs [4].The framework uses Jung for the graph datastructure, because I think it is the most powerfull. It uses Gephi's ForceAtlas layout because it empirically produced the most beautifull layouts, but it was slightly modified to support nested graphs.
I hope you will enjoy this contribution,
Cheers,
Martin
@jzy3d
[1] http://datagr4m.com/node/4
[2] https://github.com/datagr4m/org.datagr4m
[3] http://datagr4m.com/node/9
[4] http://datagr4m.com/node/5