The Blue Marble is an incredibly detailed, true-color depiction of the Earth. The Blue Marble Next Generation is an update on the original that has greater detail.
"The original Blue Marble was a composite of four months of MODIS observations with a spatial resolution (level of detail) of 1 square kilometer per pixel. Blue Marble: Next Generation offers a years worth of monthly composites at a spatial resolution of 500 meters." - From the NASA website
Monthly images from 2004 are available for SOS to show the seasonal changes on the Earth's surface. Two different versions are available. Both feature topography on land, though one features the bathymetry of the sea floor while the other simply has the oceans shaded blue.