I am begining to get the impression that to science-fiction fans below a certain age nothing exists unless it is on TV, a movie, a video/computer game, or adapted from one of those things. The whole literary side of the genre seems to be fading into obscurity. I hope I am wrong about this.
Just for myself, when it comes to non tv/movie/video game based sci fi, outside of obvious stuff like Dune, I happen to love Mike Resnick's Starship series, 4 great books not connected to outside media. For fantasy, I really enjoyed John Ringo's two Special Circumstances books, Neil Gaiman's Good Omens, and The Once and Future King. Besides that, a lot of the stuff I like is atleast somewhat connected to outside media, like The Dragonlance books, which are connected to D&D but is still a world created by the authors or John Ringo's Troy Rising trilogy which is apparently somewhat barely related to some outside story.
That said, looking at my list of books I've read (which isn't complete but is fairly comprehensive), I really haven't read that many sci fi or fantasy that are completely unconnected to anything but themselves. Then again, its hard to know whats good, and I usually have books I actually know I'll want to read taking up my time, instead of possibly wasting time on books of unknown quality.