Hm. Amusingly enough, I had never taken the time to complete a registration at Escapist as there was no real point in my opinion, until I read the title of this thread. So, just for amusement and possibly a reviewing-type of response to the OP, I decided to look into it. Shockingly enough, I saw a multitude of individuals just attempt to "flame" the novel (not that that should have been a surprise to me, though, this is the internet, after all; unintelligent statements run quite commonly here.)
Now, there was a point I was going to make here. First of which is a statement primarily directed at those incessantly "flaming" the book who haven't read it: Please take the time to pick up the novel (or any type of literature for those of you who I am guessing are the "BOOM! HEADSHOT ON SOURCE ALL NIGHT LONG!" type) and complete it before you make any full statements on it; no, the movie does -not- count; the movie, even to dedicated fans, was a considerable disappointment, employing actors striding in mediocrity and a director whom should undoubtedly be permanently removed from his far-too-tall chair.
Now, as to make a statement in response to the OP: Twilight, in and of itself, is, in my opinion, far from the greatest literary work. Though, there are many redeeming aspects that should be worked at in sections here. The most important being stated first: Twilight was a book written for young adults from a fictional young adult's standpoint. The book is written in a first-person set in the mind of a girl in her late teens. Now, the book indulges into the primary character's first love interest, and as any girl in her late teens who is brought into her first relationship: She is -infatuated- by her "lover".
Now that that has been established as to the nature of the book, let us now divulge further into the characters. The first I would like to state is the nature of the vampires, and I am going to state this with much irritation as all of the closed-minded invididuals:
Vampires are -FICTIONAL- characters; let us first establish that. I've read so many comments of " These Vampires don't act like X. These Vampires don't act like Y. These vampires are wimps! These vampires don't line up with ". Now, once you have looked at yourself like that for a moment and still believe that the Vampires presented here are "Wrong". Let us examine things from your gamers' standpoint:
Something every gamer can relate to: Zombies.
Basic concept: Zombies are undead creatures that feast on human blood and attack in a violent manner; if you are bitten, you are turned.
Left 4 Dead: No Explanation. Sh** happens.
Resident Evil: Unleashed Virus by an Underground Organization, and later on, leeches infesting the brains.
Original Zombies: Slow.
Zombies in games like Resident Evil: Fast.
Some Zombies in games/movies learn; others don't. Some are slow, some are fast. Infection type varies. But at the end of the day: They are still a -fictional- type of entity, much like a Vampire. In which case you cannot pin a specific set of characteristics to it. That, my fellow games, is fact.
Now, as far as the relationship between the main characters goes: It's unhealthy. But so are the relationships in 99% of things you are going to watch, read, or play. It's unhealthy, but it has an alluring aspect to it that draws many fans worldwide in. The suspense of what -could- happen in this type of relationship keeps people reading. So, for those of you that at the end of the day thing this is a book for insecure teenage girls, let me tell you how I am:
I am 17.
I'm a writer. I'm a gamer. I'm a musician. I've succeeded on all three fronts.
I am studying law, computer programming, and literature.
I am more confident than you; I have an ego to declare that I am "better" than you.
I've played more games than you, so, don't write me off as some guy who shouldn't be on a gamer's forum; I've read many books, particularly classics, so, you cannot write me off as unintelligent in the literary field.
And I enjoy Twilight.