Although I think Die Hard is the best action movie of all time I have to say BttF has so many more downright iconic scenes and elements. Hans Gruber can't compete with the DeLorean, running through glass barefoot just isn't Doc Brown trying to somehow untangle the extension cord in the very last second (I remember shouting at the TV: "NOOO! There's no time! The lightning will strike any second! PLUG IT IN!" Having to pick between these two movies causes me physical pain as they are both so dear to my heart. I'm going to have to go with Back to the Future. <stares at his Die Hard DVDs on the shelve, sighs, takes out his Beretta M9 from the top drawer, lays it on the desk in front of him, looks at the DVDs again, takes the gun and puts it in his mouth> Um-foffy-Hom <takes the gun out of his mouth again> I'm sorry John <puts the gun back in his mouth - fade to black> ... BAM!