Today I would like to mention about the graphs of social networks. Social network graphs could have some interesting property that could not easily be generated by random graph generators. There are so many tools and graphs for both academic researches and business challenges. The one that I know is Pajek and it is widely used. I guess that it is free but there are also commercial tools for both analysis and visualization. For example, Sentinel Visualizer is one of them and the graph of today is here.
There is still much more work to do. Especially due to the availability of social structures like facebook, twitter, I believe that visualization would take increasing attention in research community.