wow, this is a herd question...
i love so many quotes, but one of my favorites is:
Alice-"I think she's having hysterics. Maybe you should slap her."(New Moon)
or
Edward-"And it would always be that way for me too. I would always love this fragile human girl, for the rest of my limitless existance.(Midnight Sun)

I decided as long as I was going to hell, I might as well do it thoroughly.

It's like you've taken half myself away with you.

iff its out of all books then i like in eclipse when emmet says

'im so glad jasper didn't kill you, its so much more fun with you around' (to bella) it makes me crack up

"I can't understand. I can't bear this."
"You truly are one frightening little monster."
Both by Jasper Hale, the one and the only.

You are so bizarre, even for a human.
-Alice

Stupid leeches. Think they’re so superior.
-Jacob Black

If we had happy endings, we'd all be under gravestones now.
-Rosalie

I love anything that Jasper says and when Bella says
"Can vampires go into shock?" to carlisle in Breaking Dawn

my two mottos ^_^
"When life offers you a dream so far beyond your expectations, it's not reasonable to grieve when it comes to an end" -Bella (Twilight Preface)
""Love is irrational. The more you love someone, the less sense anything made." -Bella (New Moon

Forgot here's two more
"Did you Know that 'I told you so' has a brother? His name is 'shut the hell up.'" - Bella (Breaking Dawn)
"Before you Bella, my life was like a moonless night. Very dark, but there were stars - points of light an reason... And then you shot across my sky like a meteor. Suddenly everything was on fire; there was brilliancy, there was beauty. When you were gone, when the meteor had fallen over the horizon, everything went black. Nothing has changed, but my eyes were blinded by the light. I couldn't see the stars anymore. And there was no more reason for anything." Edward (New Moon)

Yes, I memorized the whole quote... I need to get a new hobby LOL

Well I like so many but my favorites are:
Bella- First Edward was a vampire. Second, there was a part of him-and I didn't know how dominant that part may be-that thirsted for my blood. Third, I was unconditionaly and irrevecobly in love with him.

my least favorite is:
Edward: I prefer brunettes.

i agree with patrisha727

"Did you know that 'i told you so' has a brother? his name is 'shut the thell up" from Bella, hihi :D (breaking dawn)

but you asked for fav. twilight line.

Stupid, shiny Volvo owner. from Bella Chapter 4, p.83

What if I’m not a superhero? What if I’m the bad guy? from Edward Chapter 5, p.92

Stupid, unreliable vampire. from Bella Chapter 8, p.156

Do I dazzle you? from Edward Chapter 8, p.168

About three things I was absolutely positive. First, Edward was a vampire. Second, there was part of him — and I didn’t know how potent that part might be — that thirsted for my blood. And third, I was unconditionally and irrevocably in love with him. from Bella Chapter 9, p.195

So what you’re saying is, I’m your brand of heroin? from bella
Chapter 13, p.267

Yes, you are exactly my brand of heroin. from Edward
Chapter 13, p.268

YOU SEE I HAVE ALLOT OF FAVOURITES LINES, CAN'T EVEN DECIDE BUT THERE STILL MORE I LIKE BUT I CAN'T KEEP POSTING LOL ^_^

When Bella askes Carlisle if vampires can go into shock.

"my monkey man"-rosalie

My all time favorite is the famous Lion and Lamb one but I'm quite partial to
"Stupid Shiny Volvo owner." because I own a volvo! LOL

When Bella Says:
"When it comes to all this enemies non-sense, I'm out. I am a neutral contry. I am Switzerland. I refuse to be affected by territorial disputes between mythical creatures. Jake is family. You are well, not exactly the love of my life, because I expect to love you for much longer than that. The love of my exsistance. I don't care who's a werewolf and who's a vampire. If Angela turns out to be a witch, she can join the party too."

bella "first, because you are bizarrely moral for a vampire."

edward "all right, i'll give you that.the cold is second. and thirdly.... well you do actualy stink, love "

eclipse chapter 24

1."Love is irrational. The more you love someone, the less sense anything made"-bella

2."Stupid Shiny Volvo Owner"-bella

3."My Monkey Man"-rosalie

4."It will be as if i never exsisted"-edward

i've held her all of one time,and already you think you have some moronic wolfy claim to her? she's mine