They're all pretty bad for you. I suppose I'd rather fall from 2 kilometers than 4 kilometers, but I don't think I'd survive either fall. Some cigarette's have the levels of poison in them, but that's mainly in Canada, I don't think American cigarettes bother telling you how much poison is in a cigarette, they wouldn't want to lose any business.
They are also putting out new and stronger cigarettes, so it can be difficult to tell which brand is the worst. The strongest that I've even seen, not that I look very hard, are John Player Special. I've also had the pleasure of smoking English cigarettes called Death, those were pretty bad too.
