Most of the science fiction and fantasy worlds I have loved over the years are not places I would want to live. In fact, many of them, I love precisely because they provide lots of challenges to the characters. I’ll refer to these as “antifavorites,” because it feels weird calling Elric’s or Conan’s savage worlds a “favorite,” nor would I want to go live in Mad Max’s world. But I still love it as far as fictional world-building goes.
Just the same, you gotta draw the line somewhere. I won’t go so far as to label Orwell’s world in Nineteen Eighty-Four a “favorite” or an “antifavorite,” even though I feel it’s incredibly important and a gorgeously designed nightmare. It appears below, but just figure that one’s kind of an exception, because it’s too ghoulish and realistic to me to “enjoy” in anything like the usual sense. What it is is a case study in how to create a Hell for your characters to make a point, and that in itself is brilliant world-building.
I also won’t differentiate the favorites from the antifavorites below. I feel like doing so would imply a belief that fantasy/science fiction is escapism….or that some SF/F is escapism. Or wish fulfillment — whatever you wanna call it. Sure, some is, some isn’t, but I’m not drawing the line. It would put up a fence between Narnia (where things are cool most of the time) and the Alien franchise (where everything sucks). I don’t really see things that way. Escapism is just travel under another name. Books are a vacation, but not all vacations are the same. You can travel to some sanitized resort and have margaritas delivered to your chaise lounge, or you can hack your way through the Amazon jungle and machete-fight with jaguar poachers.
Either way, you’re still on vacation.
Therefore, this list is limited to the places where I think the worldbuilding is kinda cool, for whatever reason, regardless of whether I’d want to hang out there. I also skipped most of the worlds that are close alternates of our own; if it wasn’t in the future or another planet/universe altogether, I more or less leapfrogged over it.
There are a lot of them. So what you get is a list. These are just the ones that spring to mind, in somewhat random order.