If you really like the person, then it doesn't matter if they smoke. What bothered me more is either:
1. Me really liking them but not allowing my feelings for them to grow because I didn't feel she was serious about quitting, and I didn't like the idea of getting emotionally invested in someone who could develop cancer in the future and die. (seriously)
2. Them viewing me trying to help them quit as me "controlling" them or telling them what to do; instead of trying to help them do what is in their best interest health-wise.
To be honest though, I remember dating my exes who were smokers. At first, it was really unattractive that they smoked. But then, when we would kiss and I would taste the cigarettes, it was kind of cute. It's like, I know it's not the most appealing thing in the world, but it's "HER", the girl I like, so I didn't mind it. After a while, I actually liked it, and thought she looked sexy when she was smoking.
In the beginning it might be unattractive, but as the guy likes you and his feelings for you start to grow, he'll understand that it's just a part of who you are, and you'll love it (but still wish you'd quit; not because he has anything against smoking, but because he wants you to be healthy).
If a guy smokes he might like the girl but on average smoking in general is a turn off, smoking and then trying to kiss is a bigger and girls that have this week crutch filled personalities that revolve around smoking and other types of things are in general very unattractive.
But the real key is if you like smoking vs if you don't, a persons sex doesn't have that much influence but the trend is it looks sad and week on girls.
I'll be the odd man out and say that I like it if a girl smokes. It's a turn-on for me. Personally I prefer cigarettes to anything else. I guess I have my limits when it comes to cigars or cigarillos. I just happen to think its sexy. There are a lot of people, this list aside, who think and feel the same way. I can't really explain it.
All in all, it doesn't matter one way or another. If you like the person a "flaw" shouldn't keep you from them. Nobody's perfect.
Your clothes smell bad, your breath smell bad and if I want to hang out with you my clothes will smell bad too.
It also shows that you don't care about your own health that much. And if you will have a child with me, how can I be sure that you will be able to quit smoking? Is my child gonna have to suffer from your smoking too?
I could go on forever about why smoking is a turn off but generally, in my experiance, smoking girls tend to be of low status and often have some personal problems.
I asked a guy and he said that its totally disgusting and he would not date a girl if she smoked and if his girlfriend started to he would try to get her to stop but if she refused he'd break up with her.