I think we would see a shift in the demographic of the smoker.
Kids smoking just to be rebellious? I'll buy that, and I think it depends on whether the parents they are rebelling against make a big deal of pot. If they say "OMG cigarettes are the devil's work!" that's what the little rebel will pick. If they are like, "You do go hell for smoking weed"... guess what!? lol

Now as for older people, I think the numbers would rise, because a lot of mature professionals would like to smoke, in theory, but the legal status and risk of finding a source keep them from pursuing it. Would you believe that a lot of people who would benefit from some smoke actually respect the law? lololol!!! If it were legal, I'd MAYBE, just maybe, finally be able to convince my mom that it would really take a bite out of her wound-tight anxiety problem, which has held her back all her life. Granted, she's a smart one and hard-working, but the times I've seen her overwhelmed and frozen by anxiety I have been SO angry that I can't jsut say, hey mom, take a break, let's go sit by the koi pond and have a smoke.

Soon...