Treemaps must be in the air or something. Derek points to the Hive Group’s treemap of population data (warning: java applet). It’s pretty cool: You can build the map according to a bunch of criteria (population, density, geographic area) and filter the included nations to only include countries of a certain size, or a given continent. Fun to tinker with. The Hive Group also offers demos of a bunch of applications of their map tools: You can treemap electronics at Amazon, top 100 tracks at iTunes, even Peet’s coffee.
Tracking the link to Hive Group back a couple of blogs, I found Neoformix, which is full of data visualization discussion, including a link to another style of treemap, radial treemaps. Visually, the radial treemaps remind me a little bit of the julia set.