"Don't waste it. Don't waste your life, Stark." Ho Yinsen
"I'll give you Stark, and you'll give me an army of metal soldiers—" Raza, before being disposed of by Stane
"Hold still, you little prick." Obadiah Stane
"Oh, no. I've never mistaken anything about you since you were a kid. Houdini's out of the bottle. We gave... a wondeful gift to the world. I'm stuck. We've done our part. Now it's time for both of us to go. No. NO!" Stane's last words in a deleted scene.
"What have you done? No...!" Johan Schmidt (aka The Red Skull), right before being apparently vaporized by the Tesseract
"It's okay, boss. This was never going to work if they hadn't have something to..." Agent Phil Coulson. He gets better.
Iron Man 3
"Savin, help! Help me!" Jack Taggert, as he explodes from Extremis
"Deputy, get this woman—" Tennessee Sheriff, before being killed by Ellen Brandt
"That all you got? A cheap trick and a cheesy one-liner?" Ellen Brandt
"What about you, Aldrich? What happens if you get too hot?" Maya Hansen, before being killed by Killian
"How did we get this shift?" Mansion Mook #1
(Referring to President Ellis) "He's not here. Try the jet stream? Speaking of which, go fish." Eric Savin, as he blows a hole in Air Force One, sending passengers flying out.
"No more false faces. You said you wanted the Mandarin. You're looking right at him. It was always me, Tony. Right from the start. I AM THE MANDARIN!" Aldrich Killian, before being defeated by Pepper Potts (who was injected with Extremis earlier)
Thor: The Dark World
"I will never tell you." Frigga, answering Malekith's question on where the Aether is, right before being killed by Kurse for not cooperating with him
(In the Dark Elf Language) "He is an enemy of Asgard. I saw him as their prisoner." Dark Elf Algrim (aka Kurse). Killed by one of his blackhole grenades on his belt after stabbing Loki.
"Do you think that this can be stopped? The Aether can not be destroyed." Malekith, before his defeat
Captain America: The Winter Soldier
"Admit it, Captain, we are, both of us, men out of time!" Arnim Zola, before a missile destroys the facility along with the computers with Zola's conscience.
"Sorry, Mr. Pierce, I forgot my phone." Rhonda, right before being killed by The Winter Soldier, who is at Pierce's home.
"What!? Are you crazy? That is a terrible, terrible idea!" SHIELD (or rather, HYDRA) Agent Jasper Sitwell, before getting thrown out of a car by The Winter Soldier