[EveningStar]

10) The Twonky - didn't care for the film - based on the classic short story by "Lewis Padgett" (Henry Kuttner and C. L. Moore)
9) The Time Travelers - saw it but don't remember it
8) Phase IV - didn't see it
7) The Space Children - didn't see it
6) I Married a Monster from Outer Space - didn't see it
5) Project Moonbase - liked it - silly fun
4) Target Earth - I don't remember if I saw this one or not
3) Rocketship X-M - liked it - depressing
2) Kronos - saw it but don't remember it
1) The Power - liked it - based on the classic novel by recently departed Frank M. Robinson

There are more suggestions in the reader comments.

[EveningStar]

ping

[cripplecreek]

A recent one I liked was Pandorum. It was a pretty original storyline with an interesting twist at the end.

[ZOOKER]

bfl

[AnAmericanAbroad]

Here’s your chance to refresh your memory with regard to “Kronos”.

https://www.youtube.com/watch?v=K_oA-1dZCTg

I liked it, and yes.....an underrated sci-fi film.

[Jack Hydrazine]

Zardoz!

[hardspunned]

Repo man with Harry Dean Stanton

[yarddog]

I thought 2001 was a lousy film.

I liked the first two “Creature From The Black Lagoon” (Gill Man) movies but the third was not so good.

“The Day the Earth Stood Still” was over rated but still OK.

Agree with “I Married A Monster From Outer Space” It was pretty good.

[ansel12]

I thought this one was interesting. “Surrogate”

http://www.imdb.com/title/tt0986263/

[Inyo-Mono]

The original 1953 version of Invaders from Mars scared the heck out of my little brother and I for years. We wouldn't go near a sand pit for decades after seeing it on TV in the 1950s.

[BillT]

Mine Enemy

[Rockpile]

They Live.

[Chainmail]

Yeesh - I'll stick to my own list:

1. This Island Earth 1955 - Faith Domergue and Rex Reason. Great story, decent special effects

2. Forbidden Planet 1956 - Walter Pigeon, Anne Francis. A real classic

3. Moon - 2009 -Sam Rockwell, Kevin Spacey. Very simple but gripping story

4. Outland - 1981. Sean Connery Frances Sternhagen - High Noon on one of Jupiter's moons but better.

5. War of the Worlds 1953. The Classic and still good - Gene Barry and Ann Robinson

[blueunicorn6]

In high school, I took my girlfriend to the drive-in movie and I saw The Twonky. I’m not sure what movie was playing. The first time you see The Twonky, you kind of lose track of everything else.

[greene66]

Odd list. “Target Earth” and “Project Moonbase” are rather boring. “The Time Travelers” is tolerable, but goofy and ultimately unsatisfying. “The Twonky” is an interesting curiosity, but hardly something I’d call good. Never cared for “Phase IV,” but haven’t seen it in decades.

“I Married a Monster...” is a sharp sci-fi outing, better than the hokey title indicates. “Rocketship X-M” is a good oldie. “Space Children” pretty decent.

[LongWayHome]

The Omega Man with Charlton Heston.

[Kartographer]

Robinson Crusoe on Mars

Alien Nation

[hwkbeer]

The Thing From Another World,one of my favorites from the 50”s Howard Hawks was attached to the film and you can tell by the way the actors deliver their lines.Pure Hawks

http://www.dailymotion.com/video/xenyj6_the-thing-from-another-world_shortfilms

[GrandJediMasterYoda]

How about “The Islamo-Nazi President”? Very scary movie.

[Rocko]

It's worth mentioning that "I Married A Monster From Outer Space" starred Tom Tryon, who later wrote the horror classics The Other and Harvest Home, among other novels.

[SkiKnee]

8) Phase IV - didn't see it

I saw this one in the theatre with my dad. I was 15 and barely remembered it until now.

Out of all of the selections, this one has the most potential for a serious SF film.