Of all the various recordings (studio or live) of Leontyne Price as Aida that I have heard over the years, this performance from Rome in 1966 takes the top prize.
Listen here.
Aida - Leontyne Price; Radamès - Giorgio Casellato Lamberti; Amneris - Mirella Parutto Boyer; Amonasro - Mario Zanasi; Ramfis - Franco Pugliese; Il Re di Egitto - Luigi Roni; Priestess - Mirella Fiorentini; Messenger - Gabriele De Julis
Conductor: Oliviero de Fabritiis