Ok so we need some new Wallpapers! I suggest the minimum size be 1280x1024, and anything larger than that is even better! Remember to remove the UI as nobody wants to see that on a Wallpaper!
Craig Fraser posted some pointers for excellent screenshots!
a)Use the pause button and zoom/move about to get the best angle
b)Use CTRL+Shift+Z to remove the UI
c)Don't forget the action! Get some fighters & explosions in there for extra flavour.
d)Feature a dominant element in your composition. For example, a close up of a structure, with ships in the distance.
e)Go to menu > options > graphics and adjust your quality settings.