If All the World's a Stage had been on that list then Rush, but since it was an 80's list I went with Live Evil. It is Black Sabbath at it its peak musically, adding Dio as the vocalist, bringing Ronnies material into one of the best sounding live performances ever, musically improving the Ozzy era material, and the atmosphere to boot just makes this a hard to beat live album from anyone.
My second choice btw was Maidens Live After Death which imo is Iron Maiden at its peak. Most of the songs on that album were an improvement to the studio versions and when that happens you've got an epic freaking live album on your hands......
........And this is why btw I rank Rush's ATWAS as such a great live album, but again it's a 70's album.