The iPOLL Databank from the Roper Center Public Opinion Archives focuses on national scope surveys and contains not only the complete question text and responses to half a million questions from as far back as 1935, but also information such as study abstracts, links to questionnaires, datasets and citation information where available.
Gallup Analytics provides access to trended data for the U.S. back to the 1930's and a decade of data from more than 160 countries. It includes data sources from Gallup World Poll, Gallup Daily Tracking, and Gallup Brain. Also try searching Gallup News Trends for aggregated reports.
Multi-country social survey designed to assess citizen attitudes about public affairs, governance, and social policy in the Arab world, and to identify factors that shape these attitudes and values. Also available through ICPSR.