Vickimess (A very tallented CG artist if I may add).
Another I could recomend is Wittswallpapers (A very large site, who also provides links to others who have works there. On the surface, seems to be quite on the "up & up" with the work portrayed there.)
Well, guess it's time for shameless advertising of my site. If you are interested in anything space related Spacewallpapers.net should fit your bill. It has loads of real astronomy photos and a gallery of some of the more well know spacescape artists.
(This has likely been asked, but I don't see a Search function for the forum anywhere...)