Bands/artists you never got to see live in their heyday, but would've liked to.

I've actually seen a good deal of the artists mentioned in this thread. I saw almost all of the rock acts that are mentioned, with the notable exception of Prince. I saw Ellington -- a model of grace and charm. I did, though, miss Coltrane, Bird and Pavarotti. My older sister saw the Beatles at the Hollywood Bowl. She yelled herself hoarse. 

Queen   
The inventors of the modern light show.

Seen a Steely Dan show. With respect to Walter the newest Steely Dan Band is in another league.

monk
coltrane
clifford brown
bill evans
ella
eva cassidy
amy winehouse

John Coltrane
Miles Davis
Jimi Hendrix
Joni Mitchell
The Band
The Grateful Dead
The Doors
Creedence Clearwater Revival
Traffic
Cream
The Velvet Underground
Bob Marley and the Wailers
The Who (with Keith Moon) - saw them twice in the early 80’s but it wasn’t the same
Roxy Music
Howlin’ Wolf
Nina Simone
Sly and the Family Stone