Joss Whedon's "Firefly" is probably the most famous. It contained a general western feel, but with specific parallels to the civil war. James Cameron's blockbuster "Avatar" has borrowed the western theme of frontier indians. "Star Wars" is traditionally based more on medieval times than western, but the cartoon series "Clone Wars" has introduced some distinctly western elements (specifically, I'm thinking of Cad Bane, see picture). And next year, "Iron Man" director Jon Favreau is making a movie out of the popular comic "Cowboys and Aliens".
Anime has used the space western theme many times, although each show seems to have a slightly different take on it. For example, there is "Cowboy Bebop" (bounty hunters), "Trigun" (wandering gunslingers), "Outlaw Star" (hired guns/bodyguards), and "Gun Sword X" (gunfighters again).So for what reason are Space Westerns used? After all, the idea that in the future the technology and culture will somehow revert to western times can't be taken very seriously. With the exception of titles like "Cowboys and Aliens" which is played for ridiculous pulp value, I think there is a common factor of most of these space westerns. In most of them, space is treated, to borrow the famous term from "Star Trek", as the final frontier. In many of these stories, as travel and colonization into space has become common, a new land has opened up. With earth serving as the "civilized" world, planets and space have become the new "western frontier". It's a simple logical step to add a few bars and western accents.
This process clearly doesn't work for some titles such as "Star Wars" that is unrelated to earth to star out with, but digging a little deeper the same core idea exists. Planetary travel has opened up, even if not in contrast to earth, new frontiers. Often in these stories, the western motifs are confined to a "desert planet" or at least a "desert sector".
So that's my basic take on space westerns. Please comment if I have left out an important titles or points. I personally find the space western to be a very compelling genre. The mix of old and new often makes a story of spaceships less boringly shiny, but more gritty and real.
