I can highly recommend everything I have read by Niven. Many of his works are really well done fairly "hard" Sci-fi, particularly the Ringworld series (the titular object is related to Dyson spheres, and has been called a "Niven ring" in his honor). I just finished Destiny's Road, and I couldn't put it down. The Mote In Gods Eye is an amazing collaboration with Pournelle, and a classic to boot. The last is the only one I saw mentioned elsewhere, but if you enjoy any of these, you'll likely enjoy the rest too.
Just finished the Mote. Nice twist on evo-psych
I have never read very much Science Fiction, unlike some of the people here on Less Wrong, and I think I would like to. At least, the few books I have read I enjoyed. I've read a couple of books from Asimov's Foundation Series, two Michael Crichton books, Twenty Thousand Leagues Under the Sea by Jules Verne, and an anthology of SciFi short stories (no really famous authors) that my dad owned.
That list looks very short. I just finished reading a fiction book, and am looking to start another. Recommendations? What are the two or three books I simply must read?