If you ask me, marijuane being illegal is like alcohol being illegal in the twenties... Did it stop anyone from drinking alcohol back than? Nope. Is the world such a horrible place because there's drunk people? Nope. Would it be if there were people stoned? Nope. Of course, about the same rules would apply as for alcohol, ie no drinking/smoking and driving, illegal for people under a certain age (this could be different depending on which country, but 18 should be a minimum).
Might I just point at Holland? Looks like it's working pretty good there, and the government is probably making a fortune out of it. People are just so bad informed about weed, it's unbelievable. Example, weed is only a gateway drug if you want it to be. I've been smoking weed for years and years now, and I will never try any hard(er) drugs.
Ah well, it's useless, since the people who decide over it are uptight politicians who know nothing about the good life I'll just keep on doing it illegally, for the time being