Choosing between Die Hard and Back To The Future is a tough call....hmmmm....I will have to go with Die Hard.
I remember being more excited by it when it came out because I had been a big fan of Moonlighting, and it was great seeing Bruce Willis step up as an action hero, whereas Alex Keaton going back in time to kiss his mum.....whilst really engaging and fun, especially when you see the thing from multiple angles as the trilogy progressed, was just slightly less exciting
I use the line "Why don't you make like a tree, and get outta here" quite a lot, but "Yippie-kai-yay" was one of the first things I taught my daughter to say!!!
So that concludes why Die Hard is better