How funny that you should post this today. The last song that played on the radio in my car before I walked into my office was N.I.B this morning. I have to admit, I am not really familiar with a ton of Black Sabbath songs, but to think they were doing that kind of music that long ago is pretty impressive. I can't think of any other band from around that time who is anything like them, so I would have to agree that they probably started the whole metal genre. Nice post!