I actually saw 2001: a Space Odyssey for the first time at my public library when I was a young kid. My older brother said it was a classic and that we should go see it. I don't even know what format it was in, because I think this was pre-video, but I remember sitting on folding chairs with about five other people to watch it projected on a portable screen. I fell asleep during the beginning ape part, but managed to stay awake for the rest, once there started to be some dialogue. I can't remember many details about the movie, but you can't forget that soothing, but creepy HAL computer voice.
I was taken back to that day as I watched Duncan Jones' relatively new sci-fi movie Moon this past weekend. In Moon, astronaut Sam Bell is at the end of his three year contract with a company that harvests energy for the earth from the moon. All alone, except for a HAL like computer named GERTY, he monitors the harvesters and sends the energy to earth. On a routine trip to check on the harvester machines, he crashes and then things start to get interesting. Jones one ups HALs creepiness by having GERTY display a simple smiley face like image that changes to reflect the computer's "emotions" while it talks.
I'm not a huge sci-fi movie fan, but I loved the mood this movie created and the plot twist that got you thinking a little. Another movie I thought captured that great eerie space atmosphere was Solaris.