Another vote for Silent Running. This movie is in mono (at least my DVD I bought is). Wonderful movie with good story and detailed sets.
2001:A Space Odyssey. A classic with beautiful cinematography and soundtrack from the genius minds of Clarke and Kubrick. I saw it at the Opera House with live orchestra on stage playing the soundtrack during the movie. Wonderful!
Logan's Run (the movie). I did enjoy the TV series as a child but later saw the original movie and preferred it.
Westworld and Futureworld if only because Yul Brynner is in it.
The Omega Man (original) and I Am Legend (remake).
As for documentaries:
Cosmos. A classic and well worth watching if only to hear Carl Sagan say "Billions"
Any
http://www.spacecraftfilms.com production. Absolutely first class historical footage.
From the Earth to the Moon. A fantastic dramatisation of the Apollo program produced by HBO. This is one of my favourites. Each mission is a separate episode as are other key events in the Apollo program.
The Right Stuff. Great movie and amazing how the actors look so much like the actual astronauts of the Mercury program. Nicely filmed.
Capricorn One. (How to fake a Mars mission). Good cast and storyline.
