Sampiro My votes:
to Bobby:
Boy, you’re teasin’ the gorilla in the monkey house.
If you weren’t my son I’d hug you.
to Luanne:
Damn it girl, every time I think you’ve said the dummest thing you could ever say you keep talking!
Miscellaneous:
Butane is a bastard gas.
Hank: So, are you Chinese or Japanese?
Kahn Souphanousinphone: I lived in Arizona for the past 20 years. I’m originally from Laos.
Hank Hill: So, are you Chinese or Japanese?
In the child rearing book by Hank Hill The Boy Aint Right, there are a list of ways to deal with your wife going through post-partum depression.
I liked the suggestion to sound-proof the garage.
Peggy to Luanne:
“You are not trailer trash just because you live in a trailer and your mama’s in jail.”
Bobby:
“I’m a little worried about being a slut.”
“Dad’s talking to the Tom Landry plate again…”
Luanne:
“At beauty school, they teach us that people aren’t black, white, red, or yellow, but their hair can be.”
Dale:
“You tell me a lot of things, Hank, most of which I publish.”
“Jokes start with ‘Knock knock’ and ‘What do you get when you cross a’”
Hank to a bunch of Christian rockers:
“Can’t you see that you’re not making Christianity better? You’re just making rock and roll worse.”
I like a quote from the episode about whether Hank Hill rented a porn tape or not. He was arguing with the video clerk, and Hank wanted to know was it the clerk’s fault, or the computer’s, so he’d know whose ass to kick. The clerk the computer was at fault, or something, and Hank said “OK. Where’s the ass on this thing?”
I say that a lot now about similar devices that piss me off.
“For three years now, I’ve had show turtles. And I’ve never once put them in a show. I’m a freaking hypocrite.”
-Dale
LUANNE (losing her temper with Uncle Hank): Good thing that I don’t have dangerous brain powers, or right now you’d be in a thousand little pieces!
Since my dad’s name is Dale, Hank’s frequent “Dammit, Dale!” is an all-time fave.
From the episode where Bobby is put on Ritalin:
Bobby: <sniffs> There’s some milk in the refrigerator that’s about to go bad… And there it goes.
My all time favorite is a cinch. When Bobby is playing baseball and Hank is playing coach from the sidelines, and Bobby won’t swing the bat…
Hank says, “You have to swing the bat, son. You can’t get on base unless you swing the bat.”
“He could walk me,” says Bobby.
“Damn it, son, we’re playing baseball, not lawyer ball.”
DAMMIT!
I’ve seen a grand total of 3 entire KOTH episodes. And that’s the one line I remember (and use as much as I can).
Dio, you ruined my day! 
Love the bobby on ritilin quote, that’s the one I was going to post.
I’m also a fan of Cotten.
There was one episode where Peggy was saying she wanted to tell him how she felt about Bobby going to military school and he said somethign to the effect of “Woman, why don’t you express your feelings in the form of a bundt cake.”
Take it from me, Chuck Mangione-unplugging your iron “feels so good.”
Mangione’s guest-voiced so many times on the show, I think he can be considered a minor character. And of course, for minor characters, there’s always the fictional Monsignor Martinez. “Vaya…con dios! BANG”
Regarding Bobby:
“it’s only 8.30 in the morning and already the boy ain’t right”.
And anything that Boomhaler (or whatever he’s called) mutters.
I think it’s “::sigh:: Six AM and already that boy ain’t right.”
My personal fave-- Dale, after Hank refuses an upgrade to a fancy room through Dale’s deceptive means: Don’t mind him, he’s with the schoolmarm convention.
Dale Gribble: Don’t lie to us, friend, 'cause when you lie, you make an ass out of you and me.
Connie: And then you killed the German Corporal?
Bobby Hill: This was World War Two, Connie-girl. He was a Nazzy.
Cotton hill: Yeah, I severed his windpipe with a two-foot strand of dental floss I kept in my boot. And that’s why it’s always important to carry dental floss.
Boomhauer: Yeah man, I tell ya what, man. That dang ol’ Internet, man. You just go on there and point and click. Talk about W-W-dot-W-com. An’ lotsa nekkid chicks on there, man. Click. Click. Click. Click. Click. It’s real easy, man.
Cotton to his newborn son: “Hey little boy! Do you wanna kill a Nazzy! Damn! Look at those perfect shins!”
Peggy to Cotton: I don’t know what I hate more about you- your chauvinism or your bigotry or your complete selfishness!
Cotton (no sense of irony): Well, think on it and get back to me.
To Bobby:
“Hod Damnit Bobby, git yur butt outs that trash can!”