if you look at the number of deaths from cigarettes it is massive. And then look at the number of deaths from weed 0. I would say it is a lot healthier to smoke weed. Plus the cannabanoids inside weed actually have cancer fighting agents in them.
here are some links
Marijuana might cause new cell growth in the brain - health - 13 October 2005 - New Scientist
and apparently it doesn't lead to lung cancer Study Finds No Cancer-Marijuana Connection - washingtonpost.com