I've been reading quite a lot of science fiction books since I was in middle school. Recently I read a couple of good ones I'd like to recommend.
"The Cyberiad" by Stanislaw Lem is a collection of closely related short stories. It is based in a future universe populated primarily by robots (in fact, only one human appears in the book, and only as a brief mention). It is a collection of adventures of two robot inventors (or "Constructors" - in the vocabulary of the book). I really liked this book, and I put it next to "Solaris" as the best Stanislaw Lem book I've read to this point.
"The Diamond Age" by Neal Stephenson is also very good. It's more mainstream than Lem's books. The back cover describes it as Science Fiction, if Quentin Tarantino was a Science Fiction writer. There's vulgarity, drugs and sex throughout. It's also the story of a girl that grows up with a kind of virtual reality childrens book as her teacher. It's really very engaging. A real page turner, which is good if that's your style of reading (not mine, usually, but I enjoyed it).
A short list of some other books I've read in the past few years and recommend:
Kurt Vonnegut - "Cat's Cradle", "Sirens of Titan", "Slaughter House 5"
Ray Bradbury - "The Illustrated Man"
Philip K. Dick - "A Scanner Darkly", "Ubik", "The Three Stigmata of Palmer Eldritch", "Do Androids Dream of Electric Sheep?" (made into the "Blade Runner" movie)
Thomas Pynchon - "Against the Day"
And some classics I read while still in high school: The "Foundation" and "Robot" series' by Asimov, especially the first three novels in the "Foundation" series, the "Dune" series by Herbert, "Stranger in a Strange Land" by Heinlein...
Of these, I think the Vonnegut and Dick novels are my favorites. I've read almost everything written by both authors.
The Pynchon novel there is fantastic, but definitely not for everyone. If you don't mind being a little lost in a novel once in a while, Pynchon is manageable. It's more in the style of Jules Verne/H.G. Wells early 20th century science fiction/fantasy, and it's a fairly challenging read, sprawling, dense and inventive, though less so than, say, "Gravity's Rainbow" or "V".
Anyone else read Science Fiction/Fantasy? (I don't mean Star Trek or D&D novels - sorry if that's your taste)