Thank you!

The greatest moment of all sci-fi for me has to be in the War of the Worlds too, with the last dying Martian crying out over a desolate London, defeated along with all his companions, after all man's weapons and devices failed, by of all things bacteria.

I'll have to think about this.

That is pretty much the definitive moment of modern sci-fi.

Matrix - all movie

Stargate SG1 - the battle at the end of Season 7 when they have to protect the ship in Antarctica / The first time we meet the Asgards

Stargate Atlantis - Atlantis rising from the sea (WOW!!!!)

Donnie Darko - the final scene (WOW!!!!)

Lost - you can say that is not a sci-fi show, but the end of first season and the end of 3 and 4 seasons - God!

Mass Effect 2  (o/)

Rogue Galaxy lol

and others

It's pretty hard to pick moments since it's usually descriptions of worlds and places that stand out for me.

There is one chase sequence in Tad William's Otherland that had my heart nearly beating out of my chest. It's near the beginning on the book where the main character is being chased in cyberspace. I was sitting in the tram with my stop coming up, trying to read faster and faster hoping she would be save before I had to get up and get out of the tram.

Best sci-fi

1. Otherland, Tad Williams                 
    best moments: Entering each new simulation

2. Rama series, Arthur C. Clarke        
    best moments: Exploring the ship and inhabitants

3. Foundation series, Isaac Asimov   
    best moments: Explanation and application of psychohistory

4. Time Oddysey series, Arthur C. Clarke / Stephen Baxter  
    best moments: Surviving the sunstorm / Battle between Alexander the Great and Atilla the hun

5. Ringworld series, Larry Niven
    best moments: Crash landing on the ring world / Escaping the ringworld through a mountain top

Star Wars (film) -- When Darth Vader killed that officer with a force choke, I was hooked. That really set up the antagonists for the film and I think it would have been a less effective story without it. Plus it was just so freaking cool.

Hyperion (novel) -- The introduction of the Shrike. When it appears, it just wrecks everything. It is literally unbeatable and a threat that defines much of the first book.

from Wikipedia:
"Surrounded in mystery, the object of fear, hatred, and even worship by members of the Church of the Final Atonement (the Shrike Cult), the Shrike's origins are described as uncertain. It is portrayed as composed of razorwire, thorns, blades, and cutting edges, having fingers like scalpels and long, curved toe blades. It has the ability to control the flow of time, and may thus appear to travel infinitely fast. The Shrike may kill victims in a flash or it may transport them to an eternity of impalement upon an enormous artificial 'Tree of Thorns,' or 'Tree of Pain' in Hyperion's distant future. The Tree of Thorns is described as unimaginably large, metallic tree, alive with the agonized writhing of countless human victims of all ages and races."

Dune (novel) -- When they take the coptor-thing out to the Spice factory, which gets attacked by a Sand Worm.  That marked the Sand Worms as forces of nature that shaped and controled the entire planet, despite all of mankind's relative power.

Alien (film) -- The scene with the flamethrower in the shaft.  One of the most tension-filled moments in cinema history.  Absolutely brilliant.

This Day All Gods Die (novel) -- There is a moment when the events of three novels turn full-circle that is pretty epic.  Angus had raped, abused, and nearly broken Morn.  Through the use of an illegal cybernetic implant, he had turned her into a literal slave.  He had come to both hate and love her.  After being broken himself, and having learned some humanity, in the third book, also through the use of illegal cybernetic implants, he ends up in a position where he cannot physically disobey Morn.  Suddenly he is her slave and the narrative turns from her being carried along by events to actually focusing on what she wants to accomplish.  It's a lot more complicated than that, of course, with both being trapped in an incredibly desperate situation, but that switch in perspective is major part of what the novels are all about.  There is so much in play here, including how much both characters have changed after what they've gone through.

Neuromancer (novel) -- When we're shown a real over-view of the world inside the novel.  For me, this was what defined cyberpunk.  It was a brilliant combination of reality and science-fiction.  It was seedy and dark, where once sci-fi had been clean and bright.  It was like our own world, with all the uglyness, only with more technology.  This changed science fiction for me as a genre.

The sword of truth series was great, although mostly the earlier volumes. I haven't read the last 2 volumes yet. The Wheel of time series is better overall and stays good. I'm anxiously awaiting the paperback version of the final volume, a memory of light. Perfect to read outside on a warm summer day. With almost 1,000 pages for the final volume (almost 12,000 pages total) the series couldn't be more epic.

I'm reading Game of Thrones mean while, but it's losing me slowly. It's getting repetitive with people attacking eachother constantly. Get on with it. Although the river battle for King's landing with liquid fire was a great moment.

Memory, Sorrow and Thorn series from Tad Williams is great too. It's been a while but exploring the ancient cultures in the deep underground was amazing.

Larry Niven, Jerry Pournelle and Steven Barnes write great fantasy too.
I greatly enjoyed Destiny's road, The burning city and the burning tower.
Legacy of Heorot and Beowolf's children are very good too. Colonizing a new planet, but not being on the top of the food chain.

The Helleconia trilogy from Brian Aldiss is one of my favorites too. Best moment, the description of and life inside the Wheel of Kharnabar.

'Consider Phlebas' from Iain Banks

The culture novels of Banks are always a fun to read and I really recommend this series to every SF-fan. In this book it is a great start, with Horza reciting the beginning of a novel with strange content to distract himself from the fact that he is executed currently in a very unpleasant way. I could name another cool thing from the culture-series, the reveal of the full name of the ship named Mistake me not ...

'Fables for Robots' from Stanislaw Lem

Well, basically the whole idea of the stories, to make fairy tales about robots. if I have to single out something, it would be 'The Three Electroknights', that was extremely funny.

'Desolation Road' from Ian McDonald and 'The Carpet Makers' from Andreas Eschbach

Although two very distinct novels, one of the basic things in both books I found very refreshing: the way all the high-tech is at work and at the same time people living in simple circumstances.

'Songmaster' from Orson Scott Card

The assasination-moment is pretty strong.

'All You Zombies' from Robert Heinlein

Well, this story only consists of time-travel-paradoxon. Every turn has surprises.

And for fun I add 'La jetée', a movie from Chris marker. It is not so surprising in itself, but for everyone already knowing 'Twelve Monkeys' to see where terry Gilliams took it's inspiration and how he transformed it.

Terminator 2

A kid and a robot made a connection, either he was programmed to or the robot though it was the right thing to do. The prefect ending to a movie which got you glued to the tv before credits rolled.

Moon

Couldn't find the pic, but f it the whole movie was a great moment. 

Cowboy Bebob

What a great character

District 9

An Alien just wants to take his son away from the slums of earth, but thanks to the jackasses of humanilty that seems impossible. This man gave everything to help them eventhough he lost everything.

And the best sifi moment ever

Looper

1 - Entering the Derelict in Alien
2 - Mos Eisley cantina in Star Wars
3 - The LA skyline in Blade Runner
4 - Opening sequence to Terminator 2
5 - Title / Intro to Escape from New York