I've seen just about every show mentioned here. The two most memorable though were a Gregg Allman solo concert where he did two encores. We were in the second balcony, by the time we got downstairs he came out a third time alone with an acoustic guitar. He sat on the edge of the stage and played a few songs for about 20 of us still in the building.
The other was the Doobie Brothers, we thought the opening act was good too. Some piano player we thought was named Billy Joe, was actually Billy Joel long before he became famous.
Almost forgot David Bowie's Diamond Dogs tour. A friend and I were wearing jeans and t shirts and felt completely out of place. Everyone else was covered in glitter.