Worldmapper is a collection of world maps, where territories are re-sized according to the subject of interest. It's a very useful visual tool for comparing countries on factors such as human and social inequality, natural resources and population. Take this example, illustrating the distribution of Child Labour: http://www.worldmapper.org/display.php?selected=135
There are nearly 700 maps, some are available as PDF posters. Worldmapper also have a series of maps on the visualisation of the world's population using a new mapping technique: Worldmapper Gridded Population Cartograms.