In this case I'd say cigarettes are less nocive. Being a drug, weed is worst, damaging your brain cells. Cigarettes are bad as well, damaging your lungs, but I think they harm you less compared with weed. Cigarettes are a social drug (similar to alcohool), an accepted one, while weed is entirelly considered a drug, and it is accepted only in a few parts of the world.
From a biochemical point of view, not to seem like i am trying to justify one from the other, but if you consider the pyrolysis of cigarettes, you will find out that on combustion, one drag of cigarette smoke into the human body, introduces over 60 known carcinogens into the human body.
Would you still like to say cigarette is the better of the two?