Never touched anything that involved snorting or injecting via a needle. Most other things I have either tried or been offered, which is what you get when you have friends that are/were heavy drug users. I might have become a big user too, but I was on anti-depressants for about half my life, and taking recreational drugs can really fuck you up when you're on those, so I was extra-cautious. That is probably also why I didn't become much of a drinker.
Never shy about pot, though. It's fairly mild, and a great way to relax(something pretty important when you're depressed a lot).
It probably sounds pathetic, but the first time I tried drugs was because I wanted to write something really cool. Worked for Grant Morrison.