My absolute favorite sci fi universe....Frank Herbert's Dune
Notice I said FRANK HERBERT'S Dune
I did NOT say Kevin Anderson's or Brian Herbert's Dune.
Ummmm it's all Frank Herbert's Dune even the other books, most of the ideas were Frank's, they just put it into book form, which from the phrasing of your comments i can tell you didn't like them as much as the first 6 (of which i have to agree with the exception of Dune Messiah, i hate that book)
Stephen King's "Dark Tower" multiverse. (Which in at least some small way, contains every piece of fiction he has ever written)
Terry Pratchett's Discworld.
Douglas Adam's Hitch Hiker's Guide to the Galaxy.
and last but CERTAINLY not least, the apocalyptic cannibal zombie vs. survivor Earth as described by the films of George A. Romero. (Night of the Living Dead, Dawn of the Dead, Day of the Dead, Land of the Dead*)