slightly off topic: thinking about the 'smoking being more addictive than heroin' thing... i think its a complex issue, to do with a lot of factors. cigarettes are available pretty much on every street corner, they're socially more acceptable, they're legal, cheap, and they're all over the tv and movies, anywhere you go you can get them easily- if you're old enough, at least.
i think these things make it harder to escape them mentally and easier to relapse if you choose to. i quit smoking a few years ago, and randomly i'll see a cigarette on tv or smell one out on the street and sometimes my brain'll still go 'oooh, you should have one', but i can think 'thats a stupid idea' and ignore the thought to smoke very easily.
but i'm not sure that in many other ways the theory applies. if you quit smoking, you feel cravings and you're a bit 'off your rocker' emotionally and a bit wonky physically for a few days, and its generally not fun, but holy crap, i wouldn't relate it to what i've seen and heard of people coming off heroin, lol.
to the op: i know this thread wasn't mainly about you quitting smoking, but i saw you say you thought it unlikely, pretty much cos its hard. i'd just like to say- if you decide you wanna quit one day- be positive, cos its really not that hard - you can totally do it- i've done it, a lot of my friends have done it, my bro has done it, even my dad who smoked for about 40 years has done it- tho sadly it took a stroke for him to quit. if you decide one day wanna do it, get help, get support, get a strategy- and remember, you can do it!