"I'd rather eat a big old bug
...than ever take a stupid drug
I like this one, it's kind of catchy. However, I have a thing about bugs, especially spiders, so if it ever really came down to it, give me any drug any day of the damn week.
A couple newer ones have caught my eye lately, the ones featuring something as the "anti-drug." Two of these anti drugs are music and dance. Now, I don't know about you, but when I add drugs to music and dance I have a hell of a good time. :) Rave: the anti-drug.