This is a bit of a macabre subject, but I find that the final words of a significant character can be powerful moments in literature and cinema, that tie in the running themes to a single moment.
My favorite of these would the Tears in the Rain soliloquy from Blade Runner.
For those who watched Blade Runner, you'll get the full potency of the whole thing (and if you haven't, I recommend that you do) and what it means about death, life, and being human. The more I listen to it, or ruminate on it, the more I find of what's being said. I can say it changed the way I looked at it all.
So, what about you guys? What were some of your favorite ones from both movies, tv, literature, or history?