And now for an opposing point of view...
2001 came out in 1968; I was in eighth grade and living in Japan. Over the next year, I went to see the movie at least 14 times, including losing the chance at a girl friend over it (I took her to the movie, then spent the remainder of the date trying to explain the movie, and that was our last date). To steal an old 7-UP ad line, 2001 was the un-movie, which is one reason why, when 2010 was made a generation later, it was much more of the traditional plot and archetypal characters that movie audiences have learned to expect. I will occasionally watch it now, but more for nostalgia than fascination, since so much of the techniques and technology in the movie is outdated.