I've just discovered Nicolas Garcia Belmonte's JavaScript Information Visualization Toolkit (JIT). Wow! This is very cool stuff (and no Flash). To quote from the web site:
The JIT is an advanced JavaScript infovis toolkit based on 5 papers about different information visualization techniques.
The JIT implements advanced features of information visualization like Treemaps (with the slice and dice and squarified methods), an adapted visualization of trees based on the Spacetree, a focus+context technique to plot Hyperbolic Trees, and a radial layout of trees with advanced animations (RGraph).
Nicolas also links to a talk by Tamara Munzner, which I've embedded below to remind myself to watch it.
