I don’t know if there is a thread already here. I’m following the guys from gtgraphics for a long time now. gtgraphics is a german graphics duo which creates outstanding space wallpapers and images. It reminds me very often to I:B and AQFE. Check it out here -> http://gtgraphics.de/de/wallpapers
In my opinion a space wallpaper must transport the feeling of huuuge scale. They use often little people and references to show the obvious difference in size/scale.
Especially this picture is very beautiful:
Just imagine you could see such volcano eruption in I:B.