Whats a good drug for a project

There are many drugs that can come in multiple forms (like cocaine), which you could focus on one branch of (crack, pure rock cocaine, etc...)
There are also drugs like heroine that you could focus on (which I believe are ONLY intravenous).
You could focus on the debatable "drug" marijuana or cannabis. 
Then there are date rape drugs. It all depends on where your interest lies.