de405 has been the basis for the Astronomical Almanac of the United States Naval Observatory since 2003 and powers the Jet Propulsion Laboratory's online HORIZONS service. Coordinates and velocities are provided for the major planets, the Sun, and Earth's Moon.
Name: DE405 (May 1997)
Years: 1600 through 2200
Report: Standish (1998) [PDF]
Size: 54 MB
The accuracy of this ephemeris is good; the position of the Earth or Mars, for example, should be accurate to within 2 km. But the more recent DE421 ephemeris provides greater accuracy, especially with respect to the Moon, and you should use it instead if you are planning a space mission. For missions to Mercury or Venus, DE423 will be an even better choice.
See DE406 if you are interested in a similar ephemeris for dates far in the past or future, or DE422 if you want high accuracy over a long time period (and have enough disk space).
To compute using this ephemeris in Python, see the jplephem package.