I'm not puting any quotes in for Volume 4 or more because they might be spoilery.

Everything else is spoiler free, so here there's no need for a warning eejit. Sorry if I spoiled earlier.

Mohinder: Man is a narcissistic species by nature. We have colonized the four corners of our tiny planet. But we are not the pinnacle of so-called evolution. That honor belongs to the lowly ****roach. Capable of living for months without food. Remaining alive headless for weeks at a time. Resistant to radiation. If God has indeed created Himself in His own image, then I submit to you that God is a ****roach.

Hiro: I have discovered powers beyond any mere mortal.
Ando: Right. You and Spock.
Hiro: Yes. Like Spock. Exactly.
[Hiro's boss suddenly grabs him by the neck and drags him back to his desk.]
Ando: Use your death grip, Spock! The death grip!

Claire: I walked through fire and I didn't get burned.

Nathan: You have any kids?
Nikki: That's another question
Nathan: Right
Nikki: One. Boy Genius.
Nathan: Boy?
Nikki: Boy
Nathan: I've got two boys. Not geniuses, just boys.

Mohinder: [voiceover] We are, if anything, creatures of habit. Drawn to the safety and the comfort of the similar. But what happens when the familiar becomes unsafe? When the fear that we've been desperately trying to avoid, finds us where we live?

D.L.: It's going to be you and me from here on out. Partners.
Micah: You mean like Batman and Robin?
D.L.: Yeah, like Batman and Robin. Only, I ain't wearing no tights. You can wear tights, I ain't wearing no tights.

[Sylar confronts Brian Davis.]
Sylar: You're broken. I can fix you.

Peter: ... I-I think he was trying to read my mind. They were all like us!
Nathan: Dysfunctional?

Matt: We didn't look everywhere. Maybe-maybe there's a secret room somewhere. 'Kay Maybe-
Superior: and maybe I can whistle the Star-Spangled Banner out of my ***.

Claude: Charles Darwin bred pigeons while he was working out his theory of evolution. Married up various permutations to get maximum potential.
Peter: What'd he mean by that? Maximum potential.
Claude: I think he meant you, friend.

Dale: Funny, I didn't hear your footsteps.
Sylar: That's because there weren't any.
Dale: That sound, in your heart. What is it?
Sylar: [smiling] Murder.

[As Peter throws Claude over his shoulder]
Claude: What are you doing?
Peter: Something unexpected.
[Jumps off of the roof of the Deveaux Building and flies away]

Claude: And when you've left New York a smoking crater we'll put that on your tombstone. "Here lies Peter Petrelli. [lashes out with his stick] He tried!

The Haitian:[to Claire] I do not need you happy, only safe.

Linderman: When my day of judgment comes, Nathan, I'll be remembered as a humanitarian. I care about the world, I just want to save it. To heal it. And for that, I need you.
Nathan: What could you possibly know about healing? (Linderman looks over at a dead plant and heals it.)
Linderman: A few things.

Sylar: This is usually the part when people start screaming.

Sylar: Hmm, looks like you dropped something. [Sylar picks up a Ninth Wonder cartoon.] A comic book that predicts the future. What will they think of next? [Sylar turns to page showing Hiro stabbing him.] You're kidding. This is how Isaac thought I'd die? Stabbed by a silly little man?
Ando: Hiro is not silly!
Sylar: You should've seen the look on his face when he tried to kill me.

Sylar: Haven't I killed you before?
Peter: Didn't take.

West: So, what are you?
Claire: Meaning what exactly?
West: Meaning are you one of them? Or one of the others?
Claire: I'm not sure I know what you're getting at.
West: Lemme break it down for you: are you a robot or an alien? 'Cause everyone in the world is one or the other.

West: So, lizards, huh?
Claire: Tell me you didn't just time that so I'd walk right past you.
West: I figured you'd be more into whales or something. Unicorns.
Claire: You know, you make a lot of assumptions. Is my hair really that blonde?
West: I think it's cool actually. I'm sort of into genetics too.
Claire: I didn't say I was into genetics.
West: You don't have to hide everything interesting about you. Biology is supposed to be our destiny. But people forget genes can change!
Claire: I thought guys like you were supposed to sit in the back of the classroom and hate everything.
West: I just found this book. It's by some Indian guy, I can barely even pronounce his name. It's about everything you're talking about. People who evolved. There's a whole chapter on regeneration!
Claire: Sorry, I left all my awesome genetics expert reading for the summer vacation.

The Haitian: You work for people?
Mohinder: A company.
The Haitian: Of course, there's always a company.

West: I take it you're annoyed.
Claire: What is it, West? Huh? What do you want from me?
West: I want you to admit you're different.
Claire: Okay, fine, I'm a freak. Alright?
West: Claire.
Claire: I am such a freak, in fact, that I have to tip-toe around this school pretending to be a brainless Barbie doll so nobody notices how different I am. 'Cause if they found out, I'd be carted off to some human zoo where I'd be poked and prodded at for the rest of my life. So yeah, West, I'm different. And you can tell the world if you want to because I'm tired of pretending to be someone I'm not.
West: Claire, shut up. (lifts her up and flies.)

Noah: Claire, your mother and I need to talk to you. About boys.
Claire: Oh please, not the sex talk again, it was painful enough the first time.

(West catches Claire after jumping from HOLLYWOOD sign)
Claire: You caught me.
West: Of course I did.
Claire: But I would have been fine.
West: I know you can heal, Claire, but I never want to see you hurt.

Elle: I accidentally set my grandmother's house on fire when I was six. Caused a blackout in four counties in Ohio when I was eight. I spent my ninth birthday in a glass room with an IV of lithium in my arm. I've lived in this building for sixteen years, ever since the shrinks diagnosed me as a sociopath with paranoid delusions - but they were just out to get me because I threatened to kill 'em. I'm 24 years old and I've never gone on a date. Never been on a roller coaster, never been swimming. And now you know everything there is to know about me. I don't have the luxury of being more interesting than that.

Mohinder: (voiceover) There are many ways to define our fragile existence. Many ways to give it meaning. But it is our memories that shape its purpose and give it context. The private assortment of images, fears, loves, regrets. For it is the cruel irony of life that we are destined to hold the dark with the light. The good with the evil. Success with disappointment. This is what separates us. What makes us human. And in the end, we must fight to hold on to.