This is a wonderful recording. You can tell from his first entrance that Tito Gobbi loved to sing Verdi's Rigoletto. Di Stefano is dead right for the Duke - though, to be picky, I always find his very top notes too thin and white. Callas is gorgeous and even tones herself down for the innocent daughter of the jester.
However, beware that there are some annoying cuts: part of the Rigoletto/ Gilda duet "Veglia o donna" and the Duke's cabaletta "Possente amor", but to hear Gobbi's close mic mezzavoce during "Piangi fanciulla" is worth the cost alone. Sure, he hams it up a bit at times, but who cares? He revelled in his art and he was a one-off interpreter of the great baritone roles.