Bryce is okay but it does things like put stars in front of the moon.  You can get maps from nasa for the moon and planets. Put them on spheres and vola, planets!

http://maps.jpl.nasa.gov/

Get  texture, bump, clouds, nightime lights, moon images, more from this site.

http://planetpixelemporium.com/planets.html

Universe image creator lets you paint stars, nebulas, and more. Great for painting backgrounds or postworking stars on finished bryce  renders.

http://www.diardsoftware.com/