(This is a compiled list from some of my friends)

You make your boyfriend wear that sparkly crap from Hot Topic.
You compare all the men in your life to Edward Cullen.
You have or want a life size cutout of Edward Cullen.
You refer to the books as the bible
You refer to Stephanie Meyer as Queen Stephanie Meyer
You make fansites for Twilight.
You have seen Twilight at least twice.
You have all the books and read and reread them over and over again.
You ask questions here about how to make yourself look like Edward or Bella or Alice or whoever.
You hate Harry Potter.
You own the Twilight sparkles from Hot Topic.
The term "Prince charming" is replaced with Edward Cullen.
You carry around an Edward Cullen key chain.
You hate Rob Pattinson's new haircut.
You get defensive when someone says Edward is creepy and a stalker
You like boys who like Twilight.
You want a volvo.
You want some of the jewelry seen in the movie.
You've taken an interest in Meyer's religion.
You want to name your kids Edward or another name from the series.
When someone asks for a good romance book, you automatically recommend Twilight.
You went or wanted to go to the midnight viewing of Twilight when it first came out.
Your name on Y!A is (your first name) Cullen, or has the word Twilight in it.
You want to change your last name to Cullen.
You write Twilight fanfiction.
You roleplay Twilight characters.
You call yourself a Twihard.
You waited in a long line late at night to get the newly released Twilight book.
You have Twilight (Edward Cullen) bed sheets.
You have Twilight (Edward Cullen) underwear (ugh... It's so creepy and disturbing).
Your heart skips a beat when you hear Edward Cullen's name.
You say, "Oh my Edward!'

You say, "Holy crow!"
You're constantly comparing Jacob and Edward.
You don't find it creepy at all that Jacob imprints on a newborn.
You become depressed when you've finished Breaking Dawn.
You constantly ask when Midnight Sun is coming out.
You want Stephanie Meyer's email address.
Your myspace layout is Twilight related.
You've quoted Twilight, especially the lion and the lamb line.
You've suddenly taken an interest in Seattle and Forks.
You didn't like New Moon as much because Edward wasn't there.
You have a Twilight themed birthday party.
You want the Twilight engagement ring.
You...fantasize...about Edward Cullen which may or may not be appropriate.

When you cry that the fourth book says 'the end'.

When you go to hunt down whoever posted most of Midnight Sun on the internet because now it won't be published.

When you've seen the movie 11 times and counting.

When your desktop, MSN icon, MSN name etc is revolved around twilight.

When you spent large amounts of money on all the twilight merchandise you can find.

When you see a Volvo, you scream but then smash it to bits when Edward's not in there.
You start calling your boyfriend "Edward" by accident.
You can't eat apples anymore b/c you think you're destroying Bella and Edward's love.

…you refuse to face the fact that Edward is fictional
-...you no longer say "OMG", but "OME" - oh my edward.
-…your standards for men were instantly raised because of Edward
-...you have OCD (Obsessive Cullen Disorder)
-…you secretly wish your boyfriend/girlfriend was a vampire
-…you accidentally address your dad as his name, like Bella
-…Volvo's are your new favourite car
-but when they cut you off you mutter "stupid shiny volvo owner"
-…you quote the books constantly
-...you've started saying "Holy Crow!"
-..."your blood smells good" is the best compliment anyone can give you
-...you suspect good looking people of being vampires
-...you find any guy that reads Twilight instantly attractive
-...you pretend Edward is sleeping next to you at night
-...you leave your window open for Edward before you go to sleep
-...your friends got you into Twilight, and they now beg you to stop talking about it
-…you can find relations to Twilight in every situation
-...you compare every guy you meet to Edward Cullen
-...you find Bella's clumsyness charming
-...you excuse yourself for "a human moment" when you need to shower
-…you have now started biting people.
-or threatened to.
-...you feel the need to say "breakfast time for the human" every morning
-…if anyone so much as looks at your books the wrong way, you start screaming at them.
-…if anyone hasn't read the books, you take it as a personal offence
-…you've already planned you and Edward's wedding
-and handed out the invitations
-…you attempt not to sleep because, if Edward doesn't need sleep, neither do you.
-...you looked up Vampires A-Z on the internet, and hyperventilated when you found the quotes from Twilight
-…you dress up as a vampire by painting your face white, putting purple under your eyes, and go out in public.
-…you suddenly find pale boys/girls really attractive
-…all someone has to say to make you cry is "Edward's not real."
-…you start thinking really embarrassing thoughts, but immediately stop, fearing that Edward heard you.
-…you worry that someone will turn into a werewolf when they get angry
-…when you fall or trip, you refer to it as a "Bella moment".
-…gold is your new favourite colour, courtesy of Edward's eyes.
-…you welcome rain so that your home can be more like Forks.
-…human baseball seems more boring than usual.
-…you carry a Twilight book with you at all times.
-…you will spend hours in front of the computer in Twilight fan groups, or searching for new Twilight information.
-…your sleep schedule is completely reversed due to the all-nighters you pulled to read the books.
-…you try to see what character your family or friends resemble.
-…your lifelong goal is to become a vampire and live with the Cullen's.
-and you actually believe you will
-…you bawled when Edward left.
-and when Edward came back
-…you now never want to tan, so you can look like a vampire.
-…when you see someone with dark eyes and think, "they must be thirsty."
-…you go back and forth from hating, to loving, to hating Jacob Black.
-or curse Taylor Lautner for making Jacob bearable
-…you constantly nag your friends to start reading Twilight, even though they don't need to, since you talk about it so much they know everything that happens.
-…you have to remind yourself to breathe when you think of Edward Cullen
…you would give anything to see Edward sparkle in the sun.
-…you cried when Alice saw Edward planning to die.
-…you wish you could blush like Bella.
-...you constantly wonder whether your blood would be appealing to vampires.
-and secretly hope it is.
-…you're convinced you are the biggest fan
-and will argue with anyone who begs to differ
-…your mom no longer threatens to ground you – but to take away your books.
-…in your mind, serial killers no longer exist. only newborn vampires do.
-…your heart flutters anytime Edward talks.
-...you burst into tears the moment Edward said "I do"
-…you make people read the books, but secretly hope they wont, so the obsession will only be yours.
-…you get very angry when someone says vampires sleep in coffins.
-or only come out at night.
-or won't show up in film.
-…you shun anyone who tries to convince you vampires don't exist
-…you get into fights with your Twilight obsessed fans over which one is going to marry Edward
-…you throw birthday parties for the characters in the books
-…you would gladly trade your life for Bella's, even if that means occasionally being attacked by vampires.
-…when you're cold, you wish you had Jacob.
-…the Twilight books are guarded with your life.
-…you will follow a silver Volvo, convinced that Edward is in it.
-and get very depressed when you realize he's not.
-…you wish you owned Bella's truck.
you attempt at being as graceful as Alice.
-and fail.
your future children's names are all names from the books.
you've bought several copies of each book to give as future presents to yourself.
you've made t-shirts that relate to Twilight.
you screamed when Bella kissed Jacob.
you find yourself subconsciously narrating your life.
you started using strawberry shampoo
you wish you had a Jacob and Edward to fight for you
you read/write, look at/draw Twilight fan fiction/fan art
you plan on moving to Forks someday.

you HAVE gone to Forks, and searched for the Cullen house
and cried when you didn't find it
Midnight Sun is like reading pure heaven

you are either thrilled that Robert Pattinson is playing Edward, or completely depressed.
you're convinced vampires exist, and you're not ashamed of it
you love when it is rainy, cloudy, or snowy out, and hate when it is sunny.
you check the weather in Forks, when you live no where near it.
you start screaming with random people who are also fans of twilight and become their best friend for 5 minutes while discussing favorite scenes.
whenever you hear thunder, you smile and cheer on Edward's team
-and wonder what fight Esme is breaking up when the thunder stops

you insist that your boyfriend suck on ice before kissing you, so his lips will be as cold as Edward's."save a volvo, ride a vampire" is your favourite motto
you get through 3/4 of the book in one day, but stretch the rest of it to last a week, so you won't have to stop reading
you organize all your Twilight Bumper Stickers into 'chronological' order based on the plot
you plan on being (and were) first in line for the Twilight movie
you moved to Forks, changed your name to Bella and acted like a danger magnet...and you are a guy.
you plan on changing your wedding vows from "till death do us part" to "for as long as we both shall live"
you are thrilled that it's now possible to have Edward's vampire babies
you named your car Edward so you can ride him all day long.
you will actually read everything on this list
the twilight trailer teaser made your heart stop beating
and made you scream
you introduce yourself to people as Mrs. Cullen

Every time you see a silver Volvo you start to hyperventilate.
You love when it rains.
You check the weather in Forks when you don't live there.
Your obsessed with any names in the books.
Clair De Lune is your favorite song.
You have birthday parties for the characters.
You plan on naming your kids Edward and Bella.
When someone asks you out, you say "sorry i'm already dating Edward Cullen."
You've read the books so many times they're starting to fall apart.
You attempt to not sleep because "if edward doesn'nt need to sleep you don't either.
You try to control your thoughts because Edward might hear them.
You suddenly find pale boys very attractive.