Heroin
Cannabis
And to Keif' Richards: it was oh so hard for me not to say cocaine with heroin, as the two are simply perfection together. Nothing on Earth, and I mean nothing, compares to a well made speedball/belushi. But I had to say cannabis instead of herb because I'm thinking long term, and I don't want to die of a heart attack at a young(ish) age.
It was also really hard to leave out a benzo like clonazepam or bromazepam, as I absolutely love benzos, and suffer from extreme persistent anxiety, however the Heroin would compensate for that.