Originally Posted by
Pensive Patrick
Brave New World by Aldous Huxley is probably my favourite science fiction book. Although written in the 30's it shows incredible foresight, and although some of the ideas seem slightly tame now, you can imagine they were incredibly risque at the time. I would recommend it to anyone, not just sci-fi fans.
Also the Mortal Engines trilogy by Philip Reeve, although aimed at teens I re-read them recently and found them even more moving and exciting than the first time... which makes me think they actually suit an older audience better. Tell the story of a future where cities move on wheels and eat eachother to survive.
At the moment I'm reading Asimov's Foundation trilogy, which I would also recommend. I guess some people might find them a bit dull, but if you have the patience you can really get into it.