The Doctor: The writing, the graffiti, all High Gallifreyan. The lost language of the Time Lords. There were days, there were many days, these words could burn stars and raise up empires. And topple gods.
Amy: What does this say?
The Doctor: "Hello, Sweetie."

Amy: Where'd you learn how to fly the TARDIS?
River Song: Oh, I had lessons from the very best.
The Doctor: Well, yeah...
River Song: It's a shame you were busy that day.

Amy: Aren't you going to introduce us?
Doctor: Amy Pond, Professor River Song.
River Song: I'm going to be a professor some day, am I? How exciting! (laughs) Spoilers!

River Song: Doctor. Can you sonic me? I need to boost the signal so we can use it as a beacon.
Amy: Ooh, Doctor. You soniced her.

The Doctor: You're still here. What part of wait in the TARDIS until I tell you it's safe was so confusing?
Amy: Oh, are you mister grumpy face today?
The Doctor: A Weeping Angel, Amy, is the deadliest, most powerful, most malevolent life form evolution has ever produced, and right now one of them is trapped inside that wreckage. And I'm supposed to climb in after it with a screwdriver and a torch, and assuming I survive the radiation long enough, assuming the whole ship doesn't just explode in my face, do something incredibly clever which I haven't actually thought of yet. That's my day, that's what I'm up to. Any questions?

(after rescuing Amy)
The Doctor: River, hug Amy.
Amy: Why?
The Doctor: Because I'm busy.

Octavian: An Angel on the loose amongst stone statues. Much harder then I prayed for.
River Song: Like looking for a needle in a haystack.
The Doctor: An Angel that looks like hay. A hay-like needle. Of death. A hay-like needle of death in a haystack of, er, statues. No, yours was fine.

Amy: So, what's a "Maze of the Dead"?
River Song: Ah, it's not as bad as it sounds. It's just a labyrinth with dead people buried in the walls. Okay, that was fairly bad.

Amy: So, what's he like? In the future, I mean. 'Cause you know him in the future, don't you?
River Song: The Doctor? Well, the Doctor's... the Doctor.
Amy: Oh. Well, that's, um... very helpful. Mind if I write that down?

Amy: Isn't there a chance this lot's just gonna collapse? There's a whole ship up there.
River Song: Incredible builders, the Aplans.
The Doctor: Had dinner with their chief architect once. Two heads are better then one.
Amy: What, you mean you helped him?
The Doctor: Uh, no. I mean he had two heads.

The Doctor: Tell me, how did you escape?
Angel Bob: I didn't escape, sir. The Angel killed me, too.
The Doctor: What do you mean, the Angel killed you, too?
Angel Bob: Snapped my neck, sir. Wasn't as painless as I expected, but it was pretty quick, so that was something.
The Doctor: If you're dead, how can I be talking to you?
Angel Bob: You're not talking to me, sir. The Angel has no voice. It stripped my cerebral cortex from my body and reanimated a version of my consciousness to communicate with you. Sorry about the confusion.

Amy: I don't need you to die for me, Doctor. Do I look that clingy?

The Doctor: Didn't anyone ever tell you, there's one thing you never put in a trap if you're smart? If you value your continued existence. If you have any plans about seeing tomorrow, there's one thing you never, ever put in a trap.
Angel Bob: And what would be that be, sir?
The Doctor: Me.

As alluded to in the fourth season episodes "Silence in the Library" and "Forest of the Dead," Professor River Song becomes another companion for the Doctor.