Hell, ban driving too.
There's a lot of people that don't do what I want them to be doing when I'm on the road. I'm putting myself at risk (and possibly others) every time i get into my car.
Or this. The economist's view (gotta love it):
What if smoking actually produces a societal benefit rather than a cost? What if the savings in Social Security and healthcare payments due to early deaths caused by smoking are greater than what is spent on providing medical care for smoking-related problems?
What is it about cigarettes that have produced a backlash that other quite dangerous products haven't?