Somewhat unfamiliar to me is the Natural Earth project, providing free raster and vector data of administrative borders, disputed areas, populated places, urban polygons and water boundaries in addition to much more.
Great for updated maps. For historical shapefiles. Check my post on the cShapes dataset.
From their website:
“We developed Natural Earth as a convenient resource for making custom maps. Unlike other map data intended for scientific analysis or military mapping, Natural Earth is designed to meet the needs of production cartographers using a variety of software applications. Maximum flexibility is a goal.”
Go to Natural Earth Website