ZFT,
The best DEM (Digital ELevation Model) that is around at the moment would be around 100 meter tiles, anything smaller than that you are getting into the military quality data, or satellite radar sounding, and that gets expensive, not only for that data, but for the storage, and processing of the large amount of data.
I was of the understanding they use something like 100 m for the open areas, and supplement this high res contour information around specific airports.
Shoreline data that most people use is called GSHHS (
Global Self-consistant Hierarchical High-resolution Shorelines) the derivatives of that dataset I would see them using would be either the high resolution (0.2 km) or interm resolution (1.0 km)