What are your favourite sci-fi books?

Iain M. Banks - all his Culture books are fantastic, but I'll single out 'Excession' since you seek titles.

Neal Stephenson's 'Anathem'

Stephen Donaldson (most famous for the Thomas Covenant tri-trilogy) wrote a 5-book 'Gap Series'. I have very fond memories of it, though it's been two decades since I read it.

Philip K. Dick wrote a tonne of good stuff (and a bit of meh) but my two favourite are Clans of the Alphane Moon (the first Dick I read), and Valis (a bit more conventional to have on the favourite list)

Ursula Le Guin also has a huge body of excellent work - Left Hand of Darkness, and The Dispossessed are my favourites.

I really loved Roger Zelazny's Lord Of Light, though I understand it's not conventionally considered his best work.

It occurs to me that the opposite category is also quite interesting. Books like Hammerfall and Snow Queen by Joan Vinge are fantasy with scifi elements that are hard to dismiss.

Ian MacDonald is another good one. My favourite of his is The Dervish House, but his others are definitely worth reading.

Charles Stross is good. Didn't get on with Accelerando, but his Laundry books are a fun mix of HP Lovecraft/Len Deighton/IT Crowd. Halting State and Rule 34 are good explorations of pervasive augmented reality and intelligent algorithms. Also Glasshouse as an exploration of post-singularity society. Never managed to finish a Cory Doctorow book though.

I found William Gibson's Bigend trilogy a slog, but I really enjoyed The Peripheral - it's a fun read.

Enders Game and Speaker for the Dead by Orson Scott Card are fantastic, but the remaining books suffer from diminishing returns (with the possible exception of Ender's Shadow). There are a lot of books in the series, but basically, the series finishes wherever you get bored reading it.

Anything by China Mieville is well worth your time.

Oh, I also really enjoyed Elizabeth Bear's Jacobs Ladder trilogy, set on a generation ship where the inhabitants have forgotten who they are and where they're going.

For some older stuff:

The Stars my Destination by Alfred Bester – I was surprised at how good it is and how well it stands up. I couldn't believe it was written nearly 50 years ago.

The Moon is a Harsh Mistress by Robert Heinlein - possibly my favourite of his. I want to start a lunar revolution with a sentient mainframe...

I'm currently working my way through all the Hugo Award winners, from 1953 up, and there's some real gems there.

Edit: On the subject of Banks movies - one scene I would love to see (in addition to the CAT escaping from The Ends of Invention) is the scene with the Ethnarch and Zakalwe in UoW, might make a splendid cold open.

"I," said the man, "am called Cheradine Zakalwe." He leveled the gun at Ethnarch's nose. "You are called dead."

I just realised how carefully worded that is...

But in SF it is sometimes hard to distinct magic from plausible albeit far fetched science. Is FTL possible given the science of tomorrow, or magic?

If you want to have (imho) really, really good SF, chec out Ted Chiang. Very low production, but he takes science in SF very seriosly. His collection of short stories is some of the best I've ever read:

http://en.wikipedia.org/wiki/Stories_of_Your_Life_and_Others

Somebody else mentioned Anathem. And if one want deep mathematics mixed with wild ideas, language theory I strongly recommend it. It is hard to get going (at least it was for me). But very rewarding. Probably the best read the last year.

Finally, if one really wants to go the "no magic" route. I strongly recommend Netptunes Brood by Charles stross. The book is based on the idea that FTL is not possible, and as a consequence how the economics behind interstellar migration and stable exchange currencies works. Bitcoing and slow money. Just that somebody actually has been considering the finance structure behind generation ships makes it worth reading.

http://en.wikipedia.org/wiki/Neptune%27s_Brood