I'm working a JS 3D graph visualization library. Think Sigma.js, but 3D. You can see a fairly lame demo here:
http://froosky.rwell.org/graphosaurus/examples/eve/
and the source:
https://github.com/frewsxcv/graphosaurus/
Check the source on the examples page if you want to see the API thus far. While progress is being made, having other contributors (especially ones with WebGL, Three.js, or graphics backgrounds) definitely helps. Please please please let me know if you have any comments about anything related to the project. If you have any ideas for demo/example graphs, please share them! I'm getting tired of staring at the EVE Online universe :P
R + ggplot2 allows you to make aesthetically pleasing charts with minimal time and code. (and more importantly, it promotes good design without detracting from the purpose of the chart)
A couple visualizations I've done using 100% R + ggplot2:
Incanter, similar to R but based upon Clojure: http://data-sorcery.org/contents/
Another good mention, in addition to D3, for client-side graphing is highcharts: http://www.highcharts.com/
I have seen D3js used for a lot of visualizations. http://d3js.org/
d3 d3js.org
These are the top blogs I follow in the data visualization space:
http://www.edwardtufte.com/tufte/
http://visual.ly/
http://www.thefunctionalart.com/
http://hbr.org/special-collections/insight/visualizing-data
http://chartporn.org/
http://www.excelcharts.com/blog/posts/
http://flowingdata.com/
http://datavisualization.ch/
http://visualization.geblogs.com/
No matter how the tools change with time, I am able to keep up to date with the field.