If there's one film genre that splits opinions more than any other, it is science fiction. To the detractors, it is a load of cinematic nonsense, intended only for teenage boys and uber-geeks. For the fans, it is the very pinnacle of cinematic inspiration, with whole worlds and universe's laid out before their very eyes.

It is a fact, though, that a lot of sci-fi flicks are dreadful. Of course, the same goes for dramas and, God help us, romantic comedies, but it is always - always - the sci-fi films that get the full brunt of derision, which is somewhat unfair when it is remembered that both Jennifer Lopez and Jennifer Aniston are still allowed to enjoy solid movie careers.

So, not everyone likes them, but those that do love them. To be honest, we're somewhere in the middle. We loved Moon, loathed Avatar, and thought Inception was okay. Each to their own.

Even though we hated James Cameron's last film, we can't deny its greatness; after all, Citizen Kane is acknowledged as being the greatest movie ever made, but we all secretly know it's all a bit dull. This is our selection of the fifteen greatest sci-fi films ever made, and if you don't agree (as we're almost certain is going to be the case), feel free to disagree...