how do you view the earlier hard rock/metal bands in comparison to the 1980s and later stuff? While Sabbath almost single handedly invented heavy metal as a music form, they clearly took a leap from what Cream, Hendrix, Steppenwolf, Deep Purple, the MC5 and maybe a few others were doing. I'd add Zeppelin but they were essentially a contemporary for Sabbath so I'm not sure you can put them in an influence category. Later groups took the Sabbath formula and some sped it up or some incorporated a little punk approach or just made it louder or had the vocals less singing and more growling. It's definitely an interesting part of rock history and not as covered as some genres because critics have never understood it. A few of my oldest son's buddies got me to listen a bit and to watch Avenged Sevenfold. Solid stuff. In that style of music Sabbath to me remains the benchmark. Also, do you put AC/DC in that category? Some days I do some I don't. On days I do they slot right behind Sabbath for me. I never got into Iron Maiden. I can hear the effort but like Hendrix I can respect them without having to listen too much. Similarly, Guns and Roses is sort of borderline, but they were tremendous before it went off the rails.