I am deeply saddened by her passing. Her performances always featured powerful vocals driven by equally powerful emotion.
But her version of Pink Floyd's "Mother," performed live in Berlin in 1990 with Roger Waters, Rick Danko, Levon Helm, and Garth Hudson, was Sinead at her most vulnerable and in my opinion, a full expression of her soul.
Audio with onstage video: https://www.youtube.com/watch?v=QRbKXACBaoc
High quality audio only: https://www.youtube.com/watch?v=LSd0Yl5mDuU