If you guys are interested in a really creepy and potent fantasy/horror/SF world in which to set an RPG, try the Night Land, which was introduced early in the last century (still seems weird, referring to the Twentieth Century as "the last century") by the great horror writer William Hope Hodgson. There's even a website devoted to the Night Land, including maps, a timeline, and new stories by modern writers (anyone can join, though it's best to read what's already out before putting in new stuff of your own). Log on at http://home.clara.net/andywrobertson/nightmap.html
and click on the center image to access the main web page.
The Night Land is a massive valley on Earth, millions of years in the future, which contains the only life---at least, the only NATURAL life---left on the planet. Even this region is filled with monsters of all sorts, ranging from fantasy giants and human hybrids to what appear to be dinosaurs and other prehistoric animals (the text says that conditions on Earth now permit the reappearance of the "Great Beasts" of old), all the way to the ghastliest creations fit for a horror or SF story. For over 20 MILLION years, the human race is bottled up in one massive fortified building/city, the Great Redoubt. Then it is destroyed, and only scattered humans survive elsewhere before the race becomes extinct. The timeline alone is impressive, and although you'd have to check to see who has the rights to these works, it would be well worth somebody's while to create a horror RPG out of this campaign world. It even has a specialized class of monster experts to be used as a character class, which name I don't have before me and am not even going to TRY and spell properly. When you're done here, check it out.