I'm a big fan of maps -- I find that they can be a great tool for illustrating a point, and for better understanding a concept. Gapminder is one of my favorite websites for this. In class the other day, one of my professors was using a different kind of map, which I found to be quite useful for his points.
Density Equalizing Cartograms are maps where sizes of countries are illustrated according to whichever variable you are assessing...so, land area obviously shows a regular map:
Nothing you haven't seen before, I know. But check out these other ones.
Total wealth distribution in 2002:
Distribution of girls in the world not enrolled in primary school:
Those with lack of basic sanitation:
Lack of Nutrition related deaths:
Military Spending in 2002:
Public Health Spending:
Check out more at: www.worldmapper.org