Castle's ringtone for his mother is Wagner's Ride of the Valkyries.

Castle: Oh, my God!... This is quite possibly the worst coffee I've ever tasted.... It's actually kind of fascinating. It tastes, like, ah (takes a swig) It tastes like a monkee peed in battery acid... Try some?
Beckett: Don't you have a book coming out today, or something?
Castle: Yeah, so?
Beckett: So? You are watching me do paperwork. It's creepy!

Patrolman: You really basing your next character on Detective Beckett?
Castle: Every artist needs a muse.
Beckett: Call me a muse again, and I will break both your legs, 'K'?
Castle: 'K'.

(Beckett just told a wife her husband was dead)
Castle: You okay?
Beckett: Yeah. Why?
Castle: Can't be easy breaking that kind of news.
Beckett: Yeah. Well... thanks for not making it a joke.
Castle: I'm a wiseass, not a jackass.

Castle: So! What's your next move? Last person to see him alive? Establish a timeline? Back for a doughnut, more really bad coffee?
Beckett: This, um, female detective of yours. Exactly how much will she be based on me?
Castle: Well, she's not to bright, and kinda slutty...
Beckett: Right, so is that wiseass or jackass?
Castle: Actually, that was jackass.
Beckett: Mmmm.
Castle: Honestly, you're not going to have anything to be embarassed about. She's going to be... she's going to be really smart, very savvy. Haunting good looks. Really good at her job. (gets a smile from Beckett at the implied compliment) And kinda slutty!

Castle: Promise not to hate me.
Beckett: I already hate you.

Castle: Other leads! Good, because we both know he didn't do it.
Beckett: Creason? What makes you think he didn't do it?
Castle: Isn't it obvious? All the evidence points to him.
Beckett: And that somehow makes him not guilty?
Castle: He's totally the red herring!
Beckett: The red herring...
Castle: 'An innocent character who appears guilty'.
Beckett: I know what a red herring is, Castle. It's a literary device used in literature. In real life, we don't dismiss a suspect because he appears too guilty. 'Sides.... I thought you wanted to arrest him?
Castle: Yeah, because he's a tool, not because he's guilty. The guy's a multimillionaire. He's not going to be dumb enough to wrap up a dead body in his own rug.

Kirby: Mr. Family Values tells his wife that he was gonna work late. Probably crash at the office. Twenty minutes later he is...(ahem) "polling his constituency"
Beckett: What about the girl?
Kirby: From what I could see she was worth every cent.
Beckett: She was a pro?
Kirby: You don't think with a body like that she's gonna swoon over his stump speeches, do you?

Esposito: Damn! Those are some seriously fine five-star class-b misdemeanors.
Ryan: Dude, between you and me, you have to pay for it?
Castle: You counting my marriages? Wait! Stop! That's the girl in the photos.
Ryan: Look at her! If I had your money...
Beckett: This isn't phone sex, Ryan, don't just pay for the two minutes that you used.

Alexis: So by trying to look smart, they were actually being stupid.
Castle: I think you just described the human condition.

Beckett: (answering phone) Beckett.
Castle: Guess who's got a date with a prostitute?

Castle: Finished your homework?
Alexis: Yeah.
Castle: You want to finish mine?
Alexis: Well, that depends. How much you offering to pay me?
Castle: I taught you well.

Alexis: Judy called. She wanted me to remind you about the reading and book signing at Broadway Books tomorrow night.
Castle: Well, that was nice of her.
Alexis: Yeah, and, if you don't show, she will...(refers to note) drip honey on your eyeballs and let loose a hundred fire ants.
Castle: Okay, what's worse. A hundred fire ants on your eyeballs, or reading to a crowd (looking at a review), 'Prose so bad it sent me screaming out into the snow'?
Alexis: You know, if you really want to feel sorry for yourself, you should read the review in The Ledger. (moves around to pull it up on his computer)
Castle: Really? What's that damned liberal elite media saying about me now?
Alexis: (reading from the review) 'Richard Castle's stirring finale, reminds us what good pulp fiction is all about: It makes us desire a world of startling imperfection, so we can rise above, so that we can become the heroes we always imagined ourselves to be.
Castle: Used to be such a good paper, to see it fallen so far, it's sad, really...
Alexis: Shut up! I'm proud of you.
Castle: Well, you remember that the next time I sing the 'peanut butter song' in front of your friends...

Ryan: Stop running, bro. Campaign's over.
Castle: Oooh. Yes.

(as Castle and Beckett summarize the results to the Captain)
Roy: And the rug?
Castle: A red herring. Nesbitt figured they were dumping a bunch of them, figured it would keep us off his trail.
Roy: Nice work. Very impressive. (walks past them) Oh, and ah, you, too, Beckett.
Beckett: (not pleased at the suggesting it was mostly Castle's "nice work") Sir!?!
Roy: (turns around, smiling) Just yanking your chain, detective...just yanking your chain.

Beckett: What kind of a name is 'Nikki Heat'?
Castle: A cop name.
Beckett: It's a stripper name.
Castle: Well, I told you she was kind of slutty.
Beckett: Change it, Castle.
Castle: Well, hang on a second. Think of the titles: 'Summer Heat'. 'Heatwave'. 'In Heat'.
Beckett: Change the name.
Castle: No.
Beckett: Yes.
Castle: No.
Beckett: Change it.
Castle: No.
Beckett: Castle.
Castle: Sorry.
Beckett: I'm not kidding you...
Castle: I have artistic integrity.
Beckett: Artistic integrity!?!? Change the name, Castle! Today!

Title: Hell Hath No Fury

The shortened version of "Hell Hath No Fury Like A Woman Scorned", meaning that, if you scorn a woman, she will go to great lengths, even self-destructive ones, to make you regret it.