For me the best recording I've heard is the complete Ravel solo piano works by Abbey Simon.
I've listen to Gieseking, Thibaudet, Casadesus and feel that Abbey Simon's musicianship is spot on. In Simon's hands, every piece is glorious. Ravel is one of my favorite composers, and I've listened to this recording countless times. I just think Simon "gets it" in a way the others don't.
I give it my highest recommendation.