Here's my order. proven effective...(from lightest to heaviest)
personally, i never go past the 4th teir

1. Weed, Alchohol
2. Shrooms
3. Acid, Ecstasy, DXM, Salvia
4. Cocaine, Ketamine, Quaaludes, Morphine
5. Heroin, Meth, Crack, GHB (just because of the coma factor)