I'd have to say I like Ozzy Sabbath the most, for being the original one and the groundbreaking albums, but Dio comes next, then Tony Martin, then Glenn Hughes. Glenn Hughes kicks a lot more ass and sings a lot better on Iommi's solo albums than on Seventh Star, IMO. I own all the Dio albums too, and they're pretty awesome (except Angry Machines, that album is just... weird).
Saladbar - It's true, you are pretty awesome.
For the Tony Martin era... The albums go like this:
The Eternal Idol - Decent album, but only real "standout" track is The Shining.
Headless Cross - Amazing album, but a bit poppy. The title track owns face. Some really cool guitar solos (I think Brian May from Queen does a guest solo on Devil and Daughter), but for some reason they left one of the coolest tracks OFF the album [Cloak & Dagger], and I can't seem to find it.
TYR - Another amazing album, with some really cool lyrical themes and less poppy of a sound. Though "Feels Good To Me" is a definite ballad, but when the distortion kicks in (and the epic guitar solo) makes up for it.
Cross Purposes - My personal favorite of all the Tony Martin era albums, it features some of his best vocal performances and some good Iommi material.
Forbidden - Yeah, definitely the bottom of this stack... My least favorite Black Sabbath album (I really like Technical Ecstasy, Born Again, and Never Say Die, just so you know), but it still has a few good tracks on it. Though I could do without "Illusion of Power" which has Ice-T rapping on it. That was a facepalm "WTF!?" moment.
Yet, Heaven and Hell, Mob Rules, and Dehumanizer are just a step above. More pounding and driving than Tony Martin era stuff. But it's ALL good.