An old favorite
To me, the greatest science fiction stories are not about the rockets, the machines, or even the adventures, they're about us, and our nature. That's why I love "The Pedestrian" by Ray Bradbury. It's short, only about 1400 words, but it shows you a serene and terrifying picture of a sterilized future world. I've come to love this story even more since it shows up occasionally on re-runs of NPR's "Symphony Space."
The rest of this site, for German students of English, has a small collection of speeches, poems, songs, and stories, many of which are quite interesting. Though there are not many selections, they are quite broad, and will occupy you for at least a little while. Cheers.