If you're looking to get more, get the self-titled. It's pretty much in-line with Paranoid and such, all trippy and jammy, assuming you like that version of Sabbath. The other one I'd recommend is Sabbath Bloody Sabbath. It's lighter and more rock than metal at times, but there are some heavy tunes, as well. It does have a couple short, weirdass fillers, but unlike the ones on Master of Reality, they are longer and outlast their welcome. The albums's still good. Technical Ecstacy and Never Say Die could be real good or disappointing; opinions tend to skew positive or way, way negative. They're a lot less heavy than the first 6 and even throw in random synths, but AFAIC, the latter has it's fair share of good tunes.