I saw LL’s thread and didn’t want to derail it.
What are your favorites?
I love anything by Dan Simmons (Hyperion/Endymion series, Ilium series), Neal Stephenson (particularly Snow Crash and The Diamond Age), Armor by John Steakley, and Orson Scott Card.
But my all-time favorite book is Neuromancer by William Gibson. I think I’ve read that book 15 times and it gets better every time.
Jay
I love the shanara series by Terry Brooks. Have read them many times and have epic battles in them. I like them better than the lord of the rings books. I also have all of the aliens/predator books and some of them are great. A few are just ok but I like the one about the aliens taking over earth.
S.M.
Enders Game by Orson Scott Card is what really introduced me to Sci-Fi when I was a young teen. I’ve enjoyed the entire story, especially Enders Shadow. 1984 and A Brave New World are what really made me the Sci-Fi book reader that I am today.
The War Against the Chtorr.
M_P
That sounds different. I’ll have to give it a read.
Jay
Me too, I thought Sci-Fi was gay until my friends convinced me to read Ender’s Game. I stole it from the library of the USS Saipan and took it to Iraq with me LOL.
Jay
Dune and Dune Messiah by Herbert, Methuselah’s Children and The Moon is a Harsh Mistress by Heinlein, Rendevous with Rama and Something Wicked this Way Comes by Clarke, Do Androids Dream of Electric Sheep by Dick and of course The Hitchhikers Guide to the Galaxy by Adams.
I’m more “old school” sci-fi:
-Asimov’s “Foundation” trilogy.
-George R. R. Martin’s “Sandkings”
-Arthur C. Clarke’s “2001: A Space Odyssey”
-Niven & Pournelle’s “Lucifer’s Hammer” (may not fall into the pure Sci-Fi genre?)
As for “Fantasy”:
-J.R.R. Tolkien’s “Lord of the Rings”, “Silmarillion”, etc…
-C.S. Lewis’ “Chronicles of Narnia”
-Ursula K. Le Guin’s “Earthsea” trilogy
-Patricia A. McKillip’s “Riddle-Master of Hed” trilogy
-Stephen Donaldson’s “The Chronicles of Thomas Covenant” trilogys (first two. Haven’t read the latest…)
Earth by David Brin is an interesting near-future sci-fi novel. These tend to be my favorites. Some older Jerry Pournelle/Larry Niven novels like Lucifer’s Hammer and Footfall. Some of my more recent favorites include the Dresden Files by Jim Butcher. While I enjoyed the War Against the Cthorr like the previous reader, nothing tweaks me off more that reading a series in the works that the author seems to abandon!
I’m old school as well"
THX-1138
1984
I am Legend
Clockwork Orange
Dune
Fahrenheit 451
2001: A space odyssey
War of the Worlds
The Time Machine
Brave New World
Slaughterhouse Five
Lucifer’s Hammer
And of course, Starship Troopers
Definately Starship Troopers. Required reading in some defense schools.
Try the Off Armagedon Reef series (three books so far) by David Weber. Excellent mix of action and battle of every imaginable kind.
John Ringo’s “Legacy of Aldenata / Posleen War” series.
http://www.johnringo.com/Books/LegacyofAldenata/tabid/1623/Default.aspx
Oldie but a goodie, hard to find- Shockwave Rider by John Brunner
Glory Road
Starship Troopers
Do Androids Dream of Electric Sheep? Original version of Blade Runner
Anything by Phillip K Dick, you can tell when a movie is made from one his stories.
A Boy and His Dog
Some of Jerry Pournell and Larry Niven , not all of them but the majority of their work
I will second any of David Webber’s works in the military science fiction realm.
Cheesy Battletech themed novels 
Such a great book, it was disappointing to me that the movie didn’t get the “I am Legend” idea across. Oh well, guess we are the privileged!
As far as Sci-fi goes:
1984
Brave New World
Dune series
Farenheit 451
2001: A Space Odyssey
Fantasy:
Lord of the Rings
Wheel of Time
Dragonlance Chronicles
The Legend of Drizzt Series (saved the best for last)
Agreed. It seems every time they move from book to film, they screw up the majority of the concept and barely resembles the book in the end.
Altered Carbon by Richard Morgan is really good, as are the subsequent books in the series.
Chasm City was good, but very dark. Revelation Space took me a few reads, but that is just due to it being extremely technical.
The Baroque Cycle by Neil Stephenson was awesome…huge fan of it, and need to read it again.
Just finished Kevin J Anderson’s Saga of Seven Suns series. Very epic in scope (7 books had better be!), and a fun ride. Not as deep as some, but still enjoyable.
(By deep I mean technical, etc…my tastes run more towards hard Scifi)