The only drug I ever tried was weed. And that was only three times, each time while drinking beer. First two times, I didn't feel a thing, third time, which was last year, I felt dizzy and sick for 10 minutes, then it was over and that was the only effect it had on me, as far as I know.
Never tried other drugs, because I was always too scared for addiction. Bit stupid when I think about it now, but I also feel it's a bit late to start trying shit now (I'm 28 and have a kid, doesn't seem ideal to start experimenting).
As for the discussion whether caffeine is a drug or not, for me it definately is. I don't like coffee and almost never drink Cola, so nearly no caffeine intake. When I do drink Cola, I get a headache, at least that was the case a couple of years ago. The weird thing is that I do sometimes drink Cola after I had beer (even if only one or two) and then I don't get a headache. Which is good for going to gigs, where they often only have beer, Cola and water.
Alcohol is the only thing I do, but most often in moderation, don't drink too much at home, when I go to gigs, it's mostly me driving, so I only have two beers. Then whenever I go to a pub or a gig in Antwerp, I get hammered, hehe.