Ghost in the Shell series is pretty good.
Heck the Japanese rule this genre. Gundam, Robotech among others.
Sci Fi is such a broad medium. To say a film is the best is dumb.
But the movies on the list don't stand a chance. Because to say a film represents Sci Fi's best means a film or series that represents the extent of what future tech is capable of amongst a particular environment.
"Star Wars" did the most for sci-fi in general. As a matter of fact it put sci-fi on the map.
" Alien and the thing" did for horror sci-fi what Star Wars did for Sci-fi period.
"2001" was a more realistic take on sci-fi......good movie
"Star Trek" was probably had the most influence on the general population and actually inspired some of are own technology we use today."
All other Sci-Fi's in general are just that Sci-Fi's.