I'm in my late 20s and have been a social smoker since I was about 16/17 on and off. I've had about 3 cigarettes in the last 12 months, though. I usually smoke when I drink, I've rarely smoked sober.
When I was younger (15/16) most of my social group smoked (and smoked weed, too). I smoked drags of weed before I ever smoked a straight cigarette, but after a while I started to enjoy the taste a bit and I suppose mentally associate it with being happy/pleasurable things.
When I started clubbing, we'd often all go out to the smoking area to get some air and have a break. Having a pack of fags and a lighter was a good way to strike up a conversation with people, so I carried on doing this when I started uni. I never smoked sober and could go weeks without smoking at all.
When I left uni, I didn't smoke much, but my boyfriend at the time did, so I'd have a fag every now and again when I was out with him. After we broke up, I didn't smoke at all for years, but last year there were a few times when I was drunk and really craved a cigarette!
The people I know who smoke are either from a working class background or into some kind of alternative sub-culture, or are heavily into drugs. The people I know who don't tend to be middle class and more straight laced. When I was a teen, I do think there were people who glamourised smoking, but I don't think that's the reason people smoked- I think it was more to do with seeing family role models who smoked or seeing it as a "rebellious" thing to do. I also know some people who got addicted to cigarettes as a by-product of smoking weed- when I was a teenager, nearly all my friends smoked weed at parties, even if they didn't smoke cigarettes at all ever.
I do think anti-smoking education has been good, but there is a certain sort of teen who will do something because they've been told not to.
I also think the prevalence of smoking weed contributes to addiction and makes it harder for people to quit.