I saw Heart in concert in the early '80's. John Mellencamp opened for them... his American Fool tour. Not sure why they paired them together, but it was a good show.
Saw Ann Wilson, Todd Rudgren, Alan Parson, John Entwhistle, and several others in the '90's doing a Beatles tribute tour. They all opened doing Beatles songs, then came out and did some of their own stuff. Ann Wilson absolutely stole that show. She's a national treasure if you ask me. What a tremendous voice. Stairway to Heaven was absolutely awesome. Jimmy Page was really digging it. Robert Plant seemed very moved by it. They mentioned it on the Letterman show the next night.