Ah the 80s what is considered the be the golden age of Sci Fi with some many classic movies.

Star Wars
Star Trek movies
Blade Runner
Alien
Predator
Terminator
Robocop
Tron
etc.

So what are you favorite sci fi movies? And I am willing to make some exceptions since some of the famous sci fi movies started earlier like Star Wars and 2001 A Space Oddyssy and Alien started in the 70s, and Planet of the Apes started in the 60s.

Me I like a lot of these movies but my 2 absolute favorites are Robocop and Star Trek II the Wrath of Khan.

I read the OP, what rules? :P

Oh and 2001 was 1968, not 70's. :D

Anyway let me throw four into the mix:

Galaxy of Terror
Cherry 2000
Flash Gordon
Lifeforce

My favorites are:
Star Wars Original Trilogy
Aliens
Akira
Mad Max 2: The Road Warrior
Royal Space Force: The Wings of Honnêamise

The rule is allowing pre 1980s movies like Alien and 2001.

But I forbid going way too far back like Buck Rogers or Plan 9 from Outer Space....but than again what about Godzilla?

Back to the Future series
Ghostbusters (the 2nd one was OK to)
Brazil
and, yeah, I'd have to tip my hat to Verhoven and say Robocop too!

Hmm

I know Back to the Future, Ghostbusters, and even ET is Sci Fi, but no they are not even on the same level of Sci Fi like Star Trek, Blade Runner, or Robocop.

My favorites were Star Wars, Aliens, and Terminator though I must admit I have never watched Bladerunner...I know my geek card has been revoked. One of these days I plan on watching it.

How could I forget Spaceballs...slot that in between Aliens and Terminator

Personally you have to pick 2 versions.

The theatrical cut which contains narration from the main character which everyone is divided on. (People in favor of it says its to the movies, "Film Noir" presentation)

Or the Final Cut which which removes it, but also added scenes that people deemed crucial like a more ambigious ending, the Unicorn, and a person more detailed death.

But in the end I sort of find Blade Runner a bit too hamfisted with its themes.

I always watch the theatrical cut first. And then if I like it. I may move on to watching the director's cut or whatever.

The Thing is one of my favorite movies of all time, but that one sort of crosses from Sci-Fi into Horror. Even though they are not the greatest cinematic works, I've always had a soft spot for Enemy Mine and The Adventures of Buckaroo BonzaiAcross the 8th Dimension.

Well it still counts because Alien, Predator, and to some degree Terminator cross horror elements in their movies.

Snob!
Ghostbusters was THE first of my youth - like Star Wars is to just about every other member of Gen X besides me (or so it seems)
I goddam LOVE that film (not that I dislike SW or anything...)

And Back to the Future? Accelerating a DeLorean to 88Mph so that the flux capacitor kicks in and... wait.... here's another for you

Bill and Ted series!
serious, not trolling - I loved those films too! (although I'll concede that technically only the 1st one counts as it was from 1989 while the 2nd was 1991)

I want to say Indy Jones too but I think that's pushing what's Sci-Fi and what's supernatural fantasy...

You're half trolling. :P The 2nd one was almost unwatchable but the 1st one is hands down one of the greatest movies ever and needs to places atop a pedestal so we can all bask in it's glory. :D

Don't forget to also read "Do androids dream of electric sheep?" by Philip K. Dick if you want to keep that card. Those who only watch the movie are plebs. :p

I'm a huge SF fan so I love most of them, but I'll go with Alien, Terminator and Mad Max 2 from that era. Those were all seminal in a way or another for me.

And since anime count apparently, I'll throw in there Captain Harlock (Albator for us French), Captain Future (aka Capitaine Flam), Ulysses 31 and of course their granddaddy, Grendizer. These kinds of anime were aired during children shows while I was a kid, and it was AWESOME!