Personally I think the age of drinking should be brought back to 18, I mean you can join the military at 18 and honestly I think cigarettes are worse for you than the occasional beer or two(or shot, depending on what you prefer).
Drinking shouldn't be made illegal again, as long as it's done in moderation, a person's fine and medical research as found that red wine can be good for the heart, so...
Cigarettes, don't smoke 'em, don't ever plan on it. It's one of those things where yes it's killing people, but they know the risks, and if the government were to ban them, then it'd just be another way of them taking control, putting them further down the trail of being 'Big Brother'(there's only so much someone can do to protect another from themselves) Ex. A doctor will worn a guy, his blood pressure's too high and prescribe medication, but it's up to the guy if he takes the meds or not. It's free will. I mean, people have high prices and the warnings, cigarette ads(other than the electric kind) are very rarely, if ever shown and definitely not on TV, so people know the price they're paying...then again, I still think that tobacco companies should just shut down, but I don't think the government should be in control of it.
As for marijuana, I go back and forth myself...it's more natural than cigarettes, it has health benefits, but it does impare judgment, but then again, so does alcohol. People are getting it now, the government knows it, they more than aware of how common the drug is despite being illegal, so I don't know.
The age of buying cigarettes should not be lowered though. I work at a gas station where we sell cigarettes regularly and I have kids coming in that look like they're 12(they're 18), and they look so vibrant and young and then I see older customers come in, who've spent years smoking and it's such a difference, even had one come in on oxygen to buy cigarettes, it's sad, so no, I don't think kids under 18 should be able to buy cigarettes, yes I know some of them get their hands on it, but, that's less than what it would be if more could buy.