It's rare that I feel that a singer simply appropriates a role or an aria and ruins other people's performances for me. Another great voice and interpretation are always theoretically possible. But they may not presently be available.
The obvious choice for a singer who can obliterate other singers' efforts is Maria Callas. I would qualify this by saying that her interpretations often do that for me, while certain other singers have equalled and perhaps surpassed her vocally in many of her roles. But in a great performance the two must go hand in hand, so I don't want to parse this too much. With Callas, more than with any other singer, I tend to come away from a performance feeling that I will never hear the total meaning of the music and drama realized so powerfully, and that there's no point in hoping for it. And this is, for the most part, without seeing her, except in my mind's eye. Where I can see her - in the second act of Tosca - the feeling is fully confirmed. I don't even care for Tosca, except in that film from Covent Garden. She and Gobbi, for me, just own the opera. Some other roles in which, for me, no one else seems likely to measure up? Medea, Lucia, Norma, Lady Macbeth, Butterfly, Carmen...
A few other sopranos who've spoiled me in certain parts are Elisabeth Schwarzkopf, who inherited the Marschallin from Lotte Lehmann, who more or less owned it before her. Lehmann also fully embodied Sieglinde, and that Walkure Act One with Melchior will surely never be equalled. Lehmann, in fact, was a singer of such exalted expressiveness that practically everything she did, at least in German opera, set a standard. Elisabeth Grummer, another German soprano, was Weber's Agathe to the very life, with her natural, artless loveliness of spirit, wonderfully different from the sophisticated Schwarzkopf; and that same fresh naturalness made her the perfect Eva. And yet the greatest single recording of Eva's music is that of the quintet from Meistersinger led by Elisabeth Schumann, a performance that breathes such an unearthly beauty that only Grummer's comes near it. That classic recording is almost enough to make you dread the next performance you'll hear.
I guess I'll leave it with the sopranos for now.