So I rarely recommend books to people. It makes me uncomfortable. People's tastes are so different, and there really is no accounting for it. Nothing would make me feel guiltier than to tell someone to read a book that I had liked, and then they go and read it and at the end feel as if they had wasted hours of their lives. Because of me.
But, since people have asked so very prettily, I will go ahead and give you some of my personal favorites in the sci-fi/fantasy genre, although most of these more closely adhere to fantasy.
The Hitchhikers Guide to the Galaxy (Trilogy) Douglas Adams
Page for page, the first book of the trilogy is one of the funniest I have ever read. The second two are good as well, and hey, its a trilogy so you gotta read them all. This is a sci-fi book, British humor. I heard the movie wasn't very good, but the movies are rarely any good.
Wicked: The Life and Times of the Wicked Witch of the West Gregory Maguire
It is what it says, a twist on the life of the famed Wicked Witch of the West. Very, very funny and clever.
The Mists of Avalon Marion Zimmer Bradley
For the Arthurian legend fans, a wonderfully written book. Is part one of a series, but it can stand alone.
DragonLance Series (Original Authors Only) Margaret Weis and Tracy Hickman
This is a set of very traditional fantasy books, with lots of elves, dwarves, wars, true love, fights against evil and such. It was so wildly popular that it spawned what seemed to be dozens of books. I put the caveat of "original authors only" because after a while, the publishing company started having other people take over the franchise, and it they never quite got it right.
Dragon Riders of Pern (Trilogy) Anne McCaffrey
One of my most favorite set of books in the fantasy genre. There is more than just the original trilogy, and the rest are very good as well.
Foundation Series Isaac Asimov
A set of very hard-core sci-fi books. Brilliantly done by one of the most famous sci-fi authors.
LiveShip Traders (Trilogy) Robin Hobb
I agree with Suzanne, this was a great set. Ships that posess a consciousness? Who could have ever thought that concept would work? But it does.
Earthsea Chronicles Ursula K. LeGuin
A well-known and well told set. Traditional and very detailed.
Ok, now, hopefully at least one of these will have sparked your interest somewhat. If you have a chance to read any of them, let me know. Uh, that is unless you didn't like them, and then you can keep it to yourself.