For those interested in world, national and local data, I highly recommend this free tool called Gapminder World. It contains a wealth of knowledge, but not only that, it shows how things have progressed over time, including:
fertility
mortality
income
CO2 emissions
life expectancy
births/deaths
disasters
economy
education
energy
environment
geography
infrastructure
health
employment
population
poverty
inequality
technology
trade
aid
investment
Gapminder.org - For a fact based world view.
Be sure to check out the video section to see how the creator uses the tool to the best of its ability. It is truly fascinating.