I saw this commercial when I was eight or nine, maybe even younger, and I'm pretty sure I only saw it once. I don't think I fully understood the words of the song at the time, but I could tell that whatever meth was, it was bad. So I guess the PSA guys reached their goal with that one. It's not something I ever forgot. Randomly that ending line ("meth, ooh! meth!") will just pop into my head, like today.
It's funny how little things like that stay with you.