I wear the cheese. It does not wear me.
Jayne: “See, that’s why I never kiss a woman on the mouth.” {Cue a priceless range of expressions from the rest of the crew, from intrigued to baffled to horrified}
Buffy: “Hey, Ken. Wanna see my impression of Gandhi?”
(mangles Ken/demon offscreen)
Lily: “Gandhi?”
Buffy: “Well, you know, if he was really pissed off.”
You forgot the next line. 
Wash: How did your brain even learn English? I’m just so curious!"
Another of the many from Serenity:
Simon: “Now River, stay behind the others. If there’s fighting, you drop to the floor and run away.” (stage whispers) “It’s okay to leave them to die.”
Mal: “Doctor, I’m taking your sister under my protection here. If anything happens to her, anything at all, I swear to you, I will get very choked up. Honestly, there could be tears.”
“Dear Diary: Today I was pompous and my sister was crazy.”
Edit- I see the best line was taken.
Hrm-
OK-
Kaylee - “Goin’ on a year now I ain’t had nothin’ twixt my nethers weren’t run on batteries!”
Mal - “Oh, God! I can’t know that!”
Jayne - “I could stand to hear a little more.”
There are maybe two or three actors in the world who could competently deliver that first line.
GILES: Quite. And it, uh, acts on-on pure instinct. No conscience, uh, uh, predatory and, and aggressive.
BUFFY: In other words, your typical male.
XANDER: On behalf of my gender, hey!
GILES: Yes, let’s not jump to any conclusions.
BUFFY: I didn’t jump. I took a tiny step, and there conclusions were.
I’ve used that tiny step line a few times myself. 
I should really stop reading this thread. Although I loved Firefly, I told myself I wouldn’t even consider watching Buffy for the foreseeable future just because I can’t really afford to get sucked into watching a multi-season show on DVD for the time being. And now here I am considering adjusting my Netflix queue.
Darn you all! :mad:
BD, you have until Thanksgiving to get through Buffy Season 4. Otherwise you’ll never understand why it’s a sham with yams. It’s a yam sham.
Ah, another favorite from Angel:
Lorne, while telling a story to the audience, cuts from the scene in which he gets beat up to say, “Okay… Ow?!”
I use that all the time.
Jayne: “I married me a powerful ugly woman.”
Mal {disguised}: “How can you go shaming me in front of new people like that?”
Jayne: “Look, if I could make you any prettier, I would!”
Mal: “You are not the man I married twelve months ago!”
And of course Jayne, the Elder and the rainstick:
“You’re…THE GUY!”
Judge: You’re a fool. No weapon forged can stop me.
Buffy: That was then.
[Xander hands her the weapon from the box, and she raises the anti-tank
rocket launcher to her shoulder.]
Buffy: This is now.
Judge: What’s that do?
Buffy: I don’t think I can face them.
Giles: Of course, you can.
Buffy: I can’t! What am I supposed say? “Sorry I almost got your throat slit. What’s the homework?”
Giles: Punishing yourself like this is pointless.
Buffy: It’s entirely pointy. I was a moron. I put my best friends in mortal danger on the second day of school.
Giles: What are you gonna do? Crawl inside a cave for the rest of your life?
Buffy: Would it have cable?
Giles: Buffy, you acted wrongly, I admit that. But believe me, that was hardly the, the worst mistake you’ll ever make. Uh, that wasn’t quite as comforting as it was meant to be.
Of the ones not named-
BUFFY, ep. 64: PANGS
Hus, a Chumash Indian vengeful spirit has been unleashed and he’s reaking havoc on the Scoobys. (Among other things, Xander comes down with syphilis as payback for the diseases that killed the Chumash.) Willow will not use her magic against Hus because she has major white liberal guilt over the treatment of the Indians.
Later, Spike’s been tied to a chair (by Buffy, not the Indians) and is being filled with arrows during the Chumash attack. They’re coming closer to his heart but Willow still won’t help.
From Once More With Feeling:
Giles: I was able to examine the bodies while the police were taking witness arias.
From Earshot:
The mentions of Pangs reminded me of a great Xander line I’d forgotten…
From Buffy vs Dracula.
XANDER: Dammit! You know what? I’m sick of this crap. I’m sick of being the guy who eats insects and gets the funny syphilis. As of this moment, it’s over. I’m finished being everybody’s butt-monkey!
From the same episode, one of the very few quotable Riley lines:
“No, sir. No more chick pit for you.”
After the Judge is blasted to little bits, the Scoobies are told to go pick up the pieces.
Cordelia: Our job sucks!
She says it so right!
Jayne muttering about explosives.
Harmony’s little speech about why she’d be a good secretary for Angel.
“The secret ingredient is otter!”
I nearly forgot one of my all-time favorite lines:
We don’t have cable, so we have to make our own fun.
Same episode:
XANDER: Do you really think that will be enough for us to fight the Dark Master?.. bater.
“Rule number one: No punching me in the face. Rule number two: When I punch YOU in the face, you tell me how you feel, so I can write it on my clipboard. Rule number three: No touching the clipboard.”
Am I bad if I can only think of two, both from Buffy?
-
Thanksgiving episode- Spike chained to the bathtub, professing his love for the soap opera Passions (‘Timmy’s stuck in the well!’)
-
Hush- Buffy giving the wrong impression to everyone by miming the staking of a demon.