But but nobody's mentioned...
The Earthsea series of Ursula Le Guin. Ok, ok, this is fantasy, not SF, but it's incomparably greater writing than most of the sf names mentioned so far. And it has the best dragons ever.
And for SF properly speaking, how about Greg Bear's Forge of God (not sure if I've got the title exactly right)? The closing chapters, watching the destruction of the earth, still give me the shudders. There were elements in "2012" from a couple of years ago that tasted a little like Greg Bear's story, perverted and cheapened. A real production of his might be able to clean that bad taste out of my mouth.