Nation Master is a massive central data source and a handy way to graphically compare nations of the world. The site is a vast compilation of data from such sources as the CIA World Factbook, UN, and OECD. Using the Nation Master form, you can generate maps and graphs on all kinds of statistics with ease.
This is a useful one-stop resource for country statistics on everything from soldiers to wall plug voltages and visitors can also view profiles of individual countries including their maps and flags, use correlation reports and scatter plots to find relationships between variables, and refer to fully integrated encyclopedia with over one million articles. Comes highly recommended.