Dan Simmons is a bit hit and miss, but his Hyperion might be a pretty good choice to read if you're going to read exactly one SF novel. It's basically a Canterbury Tales style framing story, with the protagonists' stories being pastiches that span the history of written SF from pulp-era planetary romance to post-cyberpunk. There are three sequels that are ok, but don't measure up to the first book.
Simmons' more recent Ilium/Olympos duology drives a mountain of literary references that threaten to drown any internal coherence in the rest of the story into post-9/11 crazy right-winger bat country. Still pretty entertaining on the account of Simmons really knowing how to write stuff, but more just weird than good weird.
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?