Well, I guess it depends on brand and "strenght" a lot too. Some cigarretes are undetectable after few minutes, but some others... Like Marlboro, hell, that actually seems to stick to people, walls, ground, trees... Some smell real bad to me and I am a smoker.
But, despite that, I still say that when someone smells (in relation to this), it's not in the cigs, it's in the person.