9. Apollo 13 - "Houston, we have a problem."
This is another great example of using a memorable line from the movie itself as a tagline. Most people would already have been aware of what was to come when they saw Apollo 13 for the first time but nevertheless, its a line which acts as a particularly ominous harbinger of what is to come. Much like with Ghostbusters, this tagline became almost like a catchphrase upon the film's release and entered the public lexicon to be used any time something goes badly wrong. Having one of the most memorable lines from a film as your tagline does grant it a certain extra weight and it definitely helps with its longevity. In years to come, people will still remember the line "Houston, we have a problem", which can only helpfully contribute to the enduring popularity of the film itself.