CIA World Fact Book - information on the history, people, government, economy, geography, communications, transportation, military, and transnational issues for 267 world entities.
Data Planet Guide to Statistics
EuroStat - Eurostat is the statistical office of the European Union situated in Luxembourg. Its task is to provide the European Union with statistics at European level that enable comparisons between countries and regions
Food and Agriculture Organization of the United Nations: Statistics
International Labour Organization - Labour statistics describe the size, structure, characteristics, outputs and contributions of the participants in the labour market and how these change over time
International Monetary Fund - data on IMF lending, exchange rates and other economic and financial indicators
International Statistical Agencies (U.S. Census Bureau) - Scroll to the bottom to see list.
International Trade Statistics Yearbook - United Nations Statistics Division/ Department of Economic and Social Affairs.
NationMaster - a massive central data source and a handy way to graphically compare nations. NationMaster is a vast compilation of data from such sources as the CIA World Factbook, UN, and OECD.
OECD iLibrary - Organisation for Economic Co-operation and Development
Statista Country Reports - includes key figures on economy, consumers, technology and politics
UNESCO Data Centre - over 1,000 types of indicators and raw data on education, literacy, science and technology, culture and communication.
United Nations Statistical Yearbook - annual compilation of a wide range of international economic, social and environmental statistics on over 200 countries and areas, compiled from sources including UN agencies and other international, national and specialized organizations.
United Nations Statistical Division
World Bank Data - data about development in countries around the globe, together with other datasets cited in the data catalog
World Health Organization - access to data and analyses for monitoring the global health situation