Oh yeaah! Black Sabbath is THE ultimate band in my opinion. I love the albums with Ozzy excluding "Technical ecstasy" in part, due to the rather tired sound of the band. They had some great ideas and a couple of good songs on that album, though. "Never say die" is completely underrated, featuring some higly classic material noone seems to remember. The best albums are "Sabotage" and the first one; ground-breaking in the context they were at the time. Neither album has lost one bit of the impressive power inherent in them. The rest of the Ozz-era albums are classics as well in their own right. The best Sab songs: "Black sabbath", "Megalomania", "Iron man" ( the song that started my musical life), "Hand of doom", "Symptom of the universe", "Supernaut", "Cornucopia", "Children of the grave", "Into the void", "Electric funeral", "A national acrobat", "Sabbath bloody sabbath".. the list goes on.
As for Sab with Dio, he is the only singer during whom the band could come even close to what they were. "Dehumanizer", "Heaven and hell" and "Mob rules" are good heavy metal albums. The rest of the stuff is rather sad at times, even if Iommi has to be revered for his conviction and belief in the band.