i believe marijuianna should be legal. it is no worse than alcohol...in fact a high person is more attentive than a drunk person, not to mention that marijuianna can be used for medical purpouses as well.
As for LSD and cocaine and the such, those should be legal as they have huge lasting effects on the brain
Marijuianna has no proven long term effects on the brain...therefore its no worse than alcoholic beverages. look at the Netherlands...pot is legal there and the drinking age is 16, but its a very peaceful country.