THE VERY BEST (not in any certain order):
14.Star Trek: The Motion Picture (1979) - The Director's Edition - Robert Wise's recent clean-up of this with his "Director's Edition" improved it tremendously, so it's not "motionless" any more - with its calmer and less militaristic tone than the other Star Trek films, this is now my favorite of that series
15.The Terminator (1984) - largely an action film, lots of violence, but with good SF foundation from "Outer Limits"
16.It Came From Outer Space (1953) - hampered by low budget, script sometimes sloppy, but story from Ray Bradbury is chilling, inspiring, and nice twist on invasion yarns
17.Star Wars (1977) and sequel:
18.The Empire Strikes Back (1980) - both very good as films, are more science fantasy, so not as high on this list
19.The Island of Doctor Moreau (1977) - though has some puzzling elements, this H.G. Wells story of genetic engineering is chilling as hell; acting trilogy of Michael York, Burt Lancaster, and Richard Basehart is unbeatable
20.Charly (1968) - Daniel Keyes story of man taken from mentally deficient to genius, then back, is touching and thoughtful, thanks largely to Cliff Robertson's Oscar performance; Claire Bloom good as always, but romance between the two is awkward and not in original story
21.Seconds (1966) - spooky Frankenheimer film of elderly man deciding to live in Rock Hudson's body, then finding he can't adjust; eerily-done "conspiracy" film
22.Brother From Another Planet (1984) - Joe Morton is alien who crashes on earth and is dumbstruck by human vices he sees; good social satire by writer/director John Sayles
23.The Man in the White Suit (1951) - great satire of Alec Guinness discovering fabric that won't wear out or get dirty, so both workers and management try to kill his idea
24.Frankenstein (1931) and sequel:
25.The Bride of Frankenstein (1935) - cinematic triumph, many classic scenes; Boris Karloff gives the monster pathos
26.Monkey Business (1952) - scientists Ginger Rogers and Cary Grant accidentally discover youth serum that turn them into kids with adult bodies; film is homage to '30s and '40s screwball comedies