Top 3 most dangerous, in order:
(1) - alcohol
(2) - heroin
(3) - cocaine
Top 3 most addictive, in order:
(1) - heroin
(2) - cocaine
(3) - meth
Believe it or not, barbiturates is actually almost just as dangerous and addictive as cocaine, and tobacco is almost as addictive as cocaine.
These are results from many tests.