I was wondering that as well, sorta - what counts as a good 'real' science movie? I'm having trouble thinking of anything that really focusses on the ramifications of technology on people's lives - which is what I would consider pure scifi - rather than using it basically as an aesthetic or analogy. Nothing really springs to mind that's not fantasy-in-disguise or cookie cutter action.
Has me thinking of:
Back to the Future, which has fantasy mainly as a story device.
probably also The Time Machine, same reasoning. The novel has science content, but it's still a story device, rather than a technology that shapes culture or people's lives.
Planet of the Apes, which is a fantasy adventure.
Alien, which isn't terribly sciencey
Star Wars, all fantasy
Possible examples of more pure science fiction stories, that is, explorations of the ramifications of technology:
Bicentennial Man
A.I.
The Truman Show
Eternal Sunshine of the Spotless Mind
Next
The Matrix
1984
Value judgements aside, I'm talking basically in terms of story content.