I think I know what my favorite moment in Titanfall is. I'm in a Titan when my display tells me an enemy pilot has crawled up my back. My Titan's near death anyway and I know there won't be time to hop off and shoot the pilot down. Besides, my Titan is prepared for this exact moment. Earlier, I equipped it with a kit that would eject me, cloaked, just before it was set to explode. I should be just fine.
My Titan automatically launches me into the air and I see the colors of the sky and buildings whiz by, blurring together. My eyes focus on the enemy pilot who was just attacking me. He had been launched into the air, too, upon my Titan's explosion.