I've drank a lot in my life, I've done more hard drugs than I care to remember, I've got long-term health problems from my hard drug use....Marijuana NEVER affected me negatively. I am on the side of "it's harmless, doesn't lead to drug problems (it started with a no-good boyfriend), and doesn't kill like alcohol or tobacco".
I have a roll-up in the morning and in the evening and it never once spiralled out of control, so I can't empathise with the "it leads to hard drug addiciton" arguement.
Marijuana has helped enhance my life, helped calm down other "issues" I have, and I can happily go through a week without any withdrawal. I get horrendous withdrawal from other hard/recreational drugs, and that's my own battle, but Marijuana is just an added 'bonus' to my life. Not a necessity by any means.