An alien landscape with strange plants, an ocean, and a saturn-like planet in the background. Very vivid colors and would be good for some sort of science fiction game.
A sunset scene on another foreign planet with a beautiful ice arch and slightly cloudy sky. Personally, an environment like this in a video game would captivate me and make me more interested in playing the game itself.
Thetis Moon (above)
This image reminds me of some sort of paradise in outer space. It is very similar to Planitia with the Saturn-like planet in the background, which is why it would be good for some sort of 3-dimensional outer space game.