Favorite Simpsons Treehouse of Horror segment?

The Shinning was great.

Willie burning to death while they talk about the budget, then the animation where they all start staring at him slowly, one at a time.

Martin’s dream.
Willie: “Moris. Yoo die!”

Skinner: “There’s nothing mysterious about what happende to Groundskeeper Willie. He simply disappeared. Now let’s have no more talk of this bizarre coverup.”

Marge: “I don’t see what this has to do with Groundskeeper Willie.”
Kids: “Uh…Mom, we didn’t say anything about Groundskeeper Willie.”

Willie: “When I’m finished with ye, they’ll have to do a Compost-Mortem!”

Also love Kang and Kodos:

“Abortions for everyone!”
::BOO!::
“Abortions for no one!”
::BOO!::
“Abortions for some, tiny plastic American flags for others!”
::YAAAY!::

“I am CLIN-TON! As Overlord, all will kneel before me and obey my brutal commands. End communication.”

“We must move forward, not backward, upward not forward, and always twirling, twirling, twirling towards freedom!”

Another one I haven’t seen mentioned which I loved is when Lisa’s science experiment creates Lutherans. “Hi God? This is Bob, I live in the Clock Tower.”

My favorite is, I think, “Dial Z for Zombies” for the exchange:

Lisa: Dad! we did some thing horrible!
Homer: Did you wreck the car?
Kids: no.
Homer Did you raise the dead?
Kids: YES!
<pause>
Homer: But the car’s OK?

Good one!

Treehouse of Horror V, no question. Not only does it include “Time and Punishment” and “The Shinning”, it also has “Nightmare Cafeteria”, where Lunchlady Doris agrees with Principal Skinner that it would be great if there was a common solution to both of their problems: him dealing with severe overcrowding in the Detention room, and her with being reduced to using “Grade F Meat - Mostly Circus Animals, Some Filler”.

Jimbo: It’s hard for me to clean this giant pot when you keep spilling meat tenderizer all over me. (sound of lid closing) Oh, great, now I gotta work in the dark.

Mrs. Krabappel: Mmm… Seymour, this sandwich [a “Sloppy Jimbo”] tastes so young and impudent.

Lisa: Bart, does it strike you as odd that Uter disappeared - and suddenly they’re serving us this mysterious food called “Uterbraten”?
Principal Skinner: Oh, relax, kids! I’ve got a gut feeling Uter is around here somewhere. After all, isn’t there a little Uter in all of us? In fact, you might even say we just ate Uter, and he’s in our stomachs right now! Ha-ha-ha! … Wait, scratch that one.

The only downer to that one in my opinion was the ending with the inside-out fog and dance number. It just didn’t fit and wasn’t all that funny to me. But otherwise, 100% Prime material.
Also a favorite: the one where Burns is a vampire.

Vampire Burns (on intercom): Welcome! Come in! … Ah, fresh victims for my ever-growing army of the undead.
Mr. Smithers: Sir, you have to let go of the button.
Vampire Burns: Well, son of a —

That is based on the old radio show Lights Out episode The Dark; at least the fog turning people inside out.

Other favorite quotes from Treehouses of Horror past:

Ned Flanders: “I’m making RECORD time on this fog walk!”

Kang, Space Alien (to Marge, vis-a-vis Homer, re: Maggie’s true father, i.e., himself): “You mean, you never told him?”

And the one where Homer sells his soul for a donut is one of my all time faves.

Homer: Mmm… Forbidden donut. (gulp)
Satan Flanders: Well, well! Finishing something?

Satan Flanders (it’s always the one you least suspect): Oh, you Americans and your “due process”; this is alway so much easier in Mexico. … I give you the jury of the damned! (…) Richard Nixon!
Nixon: But I’m not dead. [which he wasn’t, when originally aired] In fact, I just wrote an article for Redbook.
Satan Flanders: Listen, I did a favor for you!
Nixon (bows head): Yes, master.

And the entire starting lineup of the 1976 Philadelphia Flyers being included was awesome too, and I’m not even a hockey fan.

From “Attack of the 50 Foot Eyesores” (which I didn’t think was that great, but it had this great scene):

Wiggum ::shoots dead a “giant” rounding the corner:: “Ah, they’re not so tough.”
Lou: “Uh, chief, that was the captain of the high school basketball team.”
Wiggum: “Uh, yeah, well he was turning into a monster.”

“Your superior intellect is no match for our puny weapons!”

“Soon they will make a board with a nail so big it will destroy them all! Muahahahahaha!”

What, no votes for the “The Raven” recital?

Ha! I came in here to mention that one. James Earl Jones ftw!

“Time and Punishment” is definitely my favorite, followed closely by “Citizen Kang”. I love (and fear) the notion that there’s nothing so outrageous that the two major parties could do that could convince Americans to “throw their vote away” on a third-party candidate.

Agreed. From King Homer after Mr Burns decide to take Marge on the boat.

Mr. Burns: What do you think, Smithers?
Smithers: I think women and sea-men don’t mix.
Mr. Burns: We know what you think.

And from the Krusty doll one:
Shopkeeper: Take this object, but beware it carries a terrible curse!
Homer: Ooh, that’s bad.
Shopkeeper: But it comes with a free frogurt!
Homer: That’s good.
Shopkeeper: The frogurt is also cursed.
Homer: That’s bad.
Shopkeeper: But you get your choice of toppings.
Homer: That’s good!
Shopkeeper: The toppings contain potassium benzoate.
Homer: …
Shopkeeper: …That’s bad.
Homer: Can I go now?

I came in just to say that one, too, and was surprised the thread went so long without it.

Well there’s you’re problem! Somebody set this doll to “EVIL”!

The toaster that was a dimensional transporter was hands-down the best, I’d say, but the computerized house with Pierce Brosnan’s voice was pretty funny, too. Esp. at the end where it tries to kill itself rather than massage Patty and Selma’s feet, but they’ve disabled its self-destruct function.

[QUOTE=Homer]
“Though thy crest be shorn and shaven, thou,” I said, “art sure no (pause followed by a wink at the cheapness of the rhyme) craven…”
[/quote]
Poetry for English majors.