One of my major long-term goals in life is to license Jack Vance's Gaean Reach concept and write a game for it. This is the closest I will ever get to living in a world in which interstellar travel is not only possible but common and reasonably priced - yet you have to physically go to a travel agent to buy a ticket (and read magazines in the waiting room while you wait).
I have written about this fairly recently, but the more that the internet permeates our lives, the more nostalgic I feel for the time before it existed. It is strange, but also perhaps strangely fitting, that science fiction - a genre about the future - should be the vehicle for that nostalgia. Rebooted and retrofitted to deliver not what could be, but what could have been once, and now never will. The future that could have been ours, before we got addicted to smartphones and decided 'likes' and retweets were more important than interstellar travel.
The beauty of the Gaean Reach is also that it is also what I think of as an 'Archipelago Setting'. It is not one region, one land, or one world, but really a setting comprising potentially almost infinite worlds, each capable of possessing great depth and detail (and also great superfluousness and superficiality). The point of an archipelago setting is that it can encompass more or less anything the creator comes up with - but it will have certain thematic undercurrents which link all of its mini-settings together. The Gaean Reach, for instance, possesses mind-boggling scope (the Alastor novels are set in a cluster of 30,000 stars with a population of five trillion, and that's just one of many books and series set in the Reach), but at the same time its many worlds and locations all feel as though they were created and conceived by one man - which, of course, they were.
Other archipelago settings which spring to mind are, of course, Iain M. Banks' 'Culture' books (which I have to confess never really gelled with me), Christopher Priest's The Islanders, CJ Cherryh's Alliance-Union books, the WH40K universe, and indeed many space operas. Interestingly, of course, D&D (certainly in its 2nd edition heyday) is in a sense a very diffuse and decentralised archipelago setting, in which everybody's Special Snowflake world is really just another sphere in the Prime Material Plane; in a more metaphysical sense yet, it is an archipelago setting whose islands exist within the heads of every DM who has ever though up his or her own world or region - with sometimes many such islands residing in one head all at once.