For me there is nothing better then Pink Floyd's "The Wall". Now I understand how many may prefer the classic"Tommy" by The Who or even Rick Wakeman's "Journey to the Center of the Earth". Sure there is a strong argument to be made for "Jesus Christ, Superstar" or "God-spell", but the truth is they come close but just do not compete, IMHO.
I think that the only competition to "The Wall" would have been if Pink Floyd had constructed a rock opera film around "The Dark Side of the Moon".
Still, what do you think as far as a rock opera is concerned?