Blue Oyster Cult, I saw them on the "Black and Blue" tour, Black Sabbath, Blue Oyster Cult. Cultosaurus Erectus was just out, great album!!!
I saw Blue Oyster Cult on that tour, too!
Although I was a long time fan of BOC for many years prior to seeing them on that tour, I was much more impressed with their live performances of both their classic songs and the newer songs! I greatly enjoyed the live versions of all of the songs they played from CE. I probably have more fond, good and also a few unusual memories of that show, but I did enjoy many of them both then and to this day!
I also saw Rush on the Permanent Waves tour and was extremely impressed with their live performances, too. The first Rush album I bought soon after it was released was Fly By Night, and although 2112 was the most popular with fans at that time, FBN always remains a great favorite with me.
OT: This was a pretty tough poll, for me. I tried to think mainly of the albums with making my vote, which wasn't easy, imo, especially with remembering both of the terrific live experiences of these two fantastic bands!