edit: sry if there's repeats...three people responded by the time I posted this
Well with much personal experience with both, I will tell you that in my findings, and probably about 90% of everyone else, alcohol is more dangerous, more harmful, and has more effects than marijuana. There are 0 deaths a year from marijuana. I'm not saying people don't get stoned and do stupid things, but marijuana is not as harmful as alcohol. People are out of control when they are too drunk. You can blackout, you can die (alcohol poisoning, fights, car rides even if you aren't driving, saying the wrong thing to someone, doing something stupid you don't have control over). When you smoke, you do not think like that. Most of the time you are relaxed, you don't even want to go out and drive, unless it's to get food

. It is different for everyone I'm sure, and there are different kinds of marijuana that have different effects (high and low) but I have NEVER met or talked with someone who believes marijuana is more dangerous than alcohol.
I 100% disagree with the people who say that one is not more dangerous than the other. I don't think you can make that statement until you have done both. Not saying you can't argue that point until you've smoked weed, but it's like talking about depression if you've never had it, or never been close to anyone with it. You just can't do it.
I in no way state that marijuana is beneficial for America. I don't necessarily think anything "good" will come out of legalization, but that's not the way I would put it. I do believe crime will go down, because I have a half dozen "buddies" who have either gotten themselves killed in marijuana deals, or have been badly injured. That's just me, 17, and all of those incidents happened in the past six months. Imagine how many of those there are out there.
I think one way its beneficial is the relaxing part. I know some of you have had amazing stress in your life. Having a child at a young age, trying to make it on your own, depression, reationships, death, things you have to live with every day. Some people use it as a way to relieve stress and not worry about things so much. Some might argue that "Well it's just a temporary relief, they are only hurting themselves more and making themselves 'stupid' by smoking weed", but the concept is that you have to smoke a lot to get "stoned" to where you don't remember the night before, or to where you can't think straight, or to where you are just plain stupid. It's a way to drink without the unawareness effect, or a way to smoke ciggarettes without an addicion or health risk. Once again I'm not saying its healty.
Finally, I'd like to bring up Prohibition. One of the biggest failures in our government's history was the banning of alcohol. It was something that pushed the sexual revolution in the early 1900's. Speak-easies opened up, which were the "back alleyway" clubs that you could get alcohol in, dance, and rebel. I'd love to remember more concrete facts about the failure of Prohibition, but without looking it up again, that's all that's coming to me. The fact of the matter is that it was a huge failure. Are we making the same mistake with marijuana?
It is sad. I am a senior in high school, and it is far easier to get marijuana than it is to get alcohol. It is easier to get marijuana than it is to get tobacco.