You guys left out a bunch of my favorites:
"Stewie: Yay and God said to Abraham, "you will kill your son, Issak", and Abraham said, I can't hear you, you'll have to speak into the microphone." "Oh I'm sorry, Is this better? Check, check, check... Jerry, pull the high end out, I'm still getting some hiss back here."
Stewie: [Picking up the phone.] Hello, operator. Hello... Oh god, that's right you have to punch in the numbers nowadays. Uhhh, I should know this. Oh yes,
[dialing number]
Stewie: 867-5309, yes that's it. Wait that's not it, damn you Tommy Two-Tone. Huh, only one thing to do 111-1111, Lois? Damn. 111-1112 Lois? DAMN. 111-1113...
Li: Stewie, come complete our rainbow.
Stewie: I've got a better idea. Let's go play "swallow the stuff under the sink."
"Hello, mother. I come bearing a gift. I'll give you a hint. It's in my diaper and it's not a toaster."
Stewie Griffin: Lois! Lois! Lois! Lois! Lois! Mom! Mom! Mom! Mommy! Mommy! Mommy! Momma! Momma! Momma! Ma! Ma! Ma! Ma! Mom! Mom! Mom! Mom! Mommy! Mommy! Momma! Momma! Momma!
Lois Griffin: WHAT!?
Stewie Griffin: Hi. [runs off giggling]
Lois Griffin: What's going on down here?
Stewie Griffin: Oh, we're playing house.
Lois Griffin: That boy's all tied up.
Stewie Griffin: Roman Polanski's house.
Lois Griffin: Stewie why don't you play in the other room?
Stewie Griffin: Why don't you burn in hell?
"For the love of God, shake me! Shake me like a British nanny!"
Peter Griffin [trying to potty-train Stewie]: Maybe you don't have to pee. I'll just give you some beer, it'll run right through you.
Stewie Griffin: Beautiful. And while we're at it we can light up a dubey and watch porn.
Peter Griffin: Rea... Really?
[In car with Brian, says to police officer] We met on the Internet. He lured me into the car with promises of candy and funny stories.
Lois Griffin: Oh, I haven't been on a college campus in years. Everything seems so different.
Stewie Griffin: Really? Perhaps if you laid on your back with your ankles behind your ears that would ring a few bells.
Lois Griffin [finding note in Chris's pocket]: Huh, what's this? You know Stewie, Mommy doesn't usually read things out of Chris's pocket. She's more respectful than that.
Stewie Griffin: Whatever helps you sleep at night, bitch.
"By all means, turn me into a child star. Perhaps I can move to Californ-i-ay and wrangle me a three-way with the Olsen twins."
Meg Griffin: Oh you know from my boyfriend, Prince William, I got this beautiful watch, and this diamond tiara, and a sceptre...[goes crazy and runs away crying]
Stewie: She needs to get laid BIG TIME!
C'mon IGN, if you are going to do something, do it right or don't do it at all.
-M