Forceful about the original Star Wars? Crazy for 12 Monkeys? Soft spot for Flubber?
Total Film is running a planet-sized poll to build a definitive list of The 50 Greatest Sci-Fi Movies Ever!
Using the form below, tell us your own personal favourite sci-fi movie and, if you like, a few words (100, tops) on why you heart it so much.
We'll feed the results into a (metaphorical) results-grinder and reveal the final list sometime in the very near future.
The smartest, funniest, most artfully effusive comments will be printed as part of the feature, with - if you include details - links to social-media profiles, websites, blogs...
We were planning to print a list of science-fiction movies for inspiration. But then we realised how much work that would involve. So here's a link to the Wikipedia page on 'Science Fiction Movies'. And here's the IMDB list of top-rated sci-fi films.