The Galaxy Map
http://galaxymap.org/
A great site for spacebuffs, amateur and professional astronomers, SF writers and starship navigators. This is authoritative material on galactic cartography, presented with rigor, showing the 3D relationships of stars, nebulae, clusters, SNRs, spiral arms and other galactic objects. Lots of image data here, in multiple wavelengths, think of it as an Atlas of the Milky Way. These are not star charts, but a variety of different representations, artwork, imagery and diagrams. Great browsing and reference site, and it has the ER seal of approval.