A Trip to the Moon (1902, Georges Méliès)
Metropolis (1927, Fritz Lang)
The Day the Earth Stood Still (1951, Robert Wise)
On the Beach (1959, Stanley Kramer)
The Time Machine (1960, George Pal)
Fahrenheit 451 (1966, François Truffaut)
Planet of the Apes (1968, Franklin J. Schaffner)
2001: A Space Odyssey (1968, Stanley Kubrick)
THX 1138 (1971, George Lucas)
The Omega Man (1971, Boris Sagal)
Soylent Green (1973, Richard Fleischer)
Rollerball (1975, Norman Jewison)
Logan’s Run (1976, Michael Anderson)
The Boys from Brazil (1978, Franklin J. Schaffner)
Mad Max (1979, George Miller)
Alien (1979, Ridley Scott)
Blade Runner (1982, Ridley Scott)
WarGames (1983, John Badham)
The Terminator (1984, James Cameron)
1984 (1984, Michael Radford)
RoboCop (1987, Paul Verhoeven)
Gattaca (1997, Andrew Niccol)
The Postman (1997, Kevin Costner)
The Matrix (1999, The Wachowskis)
A.I. Artificial Intelligence (2001, Steven Spielberg)
The Day after Tomorrow (2004, Roland Emmerich)
V for Vendetta (2005, James McTeigue)
District 9 (2009, Neill Blomkamp)
Inception (2010, Christopher Nolan)
Cloud Atlas (2012, The Wachowskis and Tom Tykwer)

List and vote for your favorite sci-fi movies.

The OP's selection gets my vote for the KJ's most arbitrary poll choices of all time!

(...and you can choose all 20 of 'em, no less. )

Why not do this as a voting poll instead, where people list their top ten in order and so on?

I'll run it if you don't want to.

LOL, I got most of my poll choices from an article on science and fantasy in movies published in Taiwan's "Science Monthly". I liked its categorization of movies by themes, e.g. space/physics, class/social justice, Dystopian, war/disaster, environment. I picked the movies I have seen and some I have come to like.

Yeah, you can pick as many favorites as you want. No restriction.

Good idea. You can go ahead and run a poll.

2. Blade Runner
3. A.I. Artificial Intelligence
4. The Truman Show
5. Gattaca

2. The Terminator
3. Terminator 2: Judgement Day
4. Oblivion
5. War of the Worlds (2005)
6. Demolition Man
7. Minority Report
8. Face/Off
9. Total Recall (1990)
10. The Matrix Revolutions

I don't see how V for Vendetta is science fiction. Surely it's political-fiction, no? It was based on a comicbook, so I suppose Man of Steel can also be considered science fiction? I wouldn't really label it as so, but if V is, then...

I thought there was one a while ago, but that was pretty recent. OK, I won't do one then.