MIT's geodata repository contains building outlines for Cambridge, Boston metro area, Houston, Manhattan and New Orleans. Detailed parcel data is available for New York City and Boston. New data is continually added so search to find the latest data.

A comprehensive, statewide database of spatial information for mapping and analysis supporting emergency response, environmental planning and management, transportation planning, economic development, and transparency in state government operations

OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
**Download data in shapefile format from: http://www.geofabrik.de/data/download.html

The download server has excerpts and derived data from the OpenStreetMap dataset available for free download in a .shp format. Most of these files are updated every day – any change you upload to OpenStreetMap should be on the download server the next day

Building outlines for metropolitan areas around the US.

A comprehensive, statewide database of spatial information for mapping and analysis supporting emergency response, environmental planning and management, transportation planning, economic development, and transparency in state government operations

The TIGER/Line files are a digital database of geographic features, such as roads, railroads, rivers, census statistical boundaries, etc. covering the entire United States. The data base contains information about these features such as their location in latitude and longitude, the name, the type of feature, address ranges for most streets, the geographic relationship to other features, and other related information. They are the public product created from the Census Bureau's TIGER database. TIGER files can be used as a detailed detailed street source and for geocoding.

This set of data includes many layers for the world, such as country boundaries, UTM zones, water, roads, railroads, airports, major cities, topography/bathymetry, and a nighttime view.

The CTPP data product, based on American Community Survey (ACS) data, is designed to help transportation analysts and planners understand where people are commuting to and from, and how they get there. The information is organized by where workers live, where they work, and by the flow between those places.

The National Transportation Atlas Database is a set of nationwide geographic databases of transportation facilities, transportation networks, and associated infrastructure. These datasets include spatial information for transportation modal networks and intermodal terminals, as well as the related attribute information for these features.

Historic railroad .shp and .kml files that were created as a part of a project on visualizing railroad history.

Available at: Rotch Library - GIS Collection | DVDROM G5701.A4 2009.E87
Includes detailed transportation data (major roads, roads, railroads and ferries), land cover and land use for Europe. It can be used for geocoding European addresses.

OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
**Download data in shapefile format from: http://www.geofabrik.de/data/download.html

This set of data includes many layers for the world, such as country boundaries, UTM zones, water, roads, railroads, airports, major cities, topography/bathymetry, and a nighttime view.

NOAA Electronic Navigational Charts (NOAA ENC®) are vector data sets. NOAA ENCs conform with the International Hydrographic Office (IHO) S-57 international exchange format, comply with the IHO ENC Product Specification, and are provided with incremental updates that supply Notice to Mariners corrections and other critical changes. NOAA ENCs and updates are available for free download.