Not to start a debate or change the thread, but I'm of the opinion that it should be treated just like gardening. I've got my plants, my wife has hers (miscellaneous house plants), and my kids and I started a little herb garden. I don't discuss them any differently with the kids: they're plants. In much the same way that I don't hide or sneak around about house plants or the herb garden, I don't hide or sneak around about my plants. Similarly, I don't hide liquor bottles from their sight, or my smokable. If any kid watching any sporting event can see a beer commercial and not become an instant drunk, those same kids can see a jar of bud and not become an instant pothead.
Plants are plants, and adult things (smoke, drink, power tools and kitchen knives) don't belong in kid's hands, period.
Then again, I live in Colorado, where I have a medical card, and now have a constitutional right to enjoy marijuana for leisure. Nevertheless, I think this was one of the greatest victories for the legalization movement: pot smokers no longer have to hide. While federal law is yet to catch up, the national tide of public opinion reached the tipping point, and there's no turning back. It takes some time getting used to, but make the mental switch: you no longer need to hide in the shadows; you no longer need to fear the white crown victoria in the rear view, simply because you have a sack; you no longer need to treat marijuana as a schedule 1 drug that, according to society, should be shunned. We're winning.