Don't really like many Verdi operas. Exceptions: Don Carlo and Otello. I think Puccini is musically more adventurous.
Never seem to tire of Strauss: Salome; Wagner: Tristan & Isolde, Walkuere; Tchaikovsky: Queen of Spades and Eugene Onegin; Mozart: Don Giovanni; Massenet: Werther. And probably one or two others.