Whenever the discussion of live performances comes up, I always pipe up immediately and say that the best live performance I've ever heard and am likely to ever hear was when I heard Whitney Houston sing in concert at Radio City not too long after the release of "The Body Guard".
She came out on stage with nothing more than an orchestra, a microphone and a chair and began to sing. Her voice was like nothing I'd ever heard before. The purity of tone and the sheer power of it literally made me weep. You could feel her voice reverberate in your chest. If you've never heard her sing live, you really don't know how extraordinary she was as a singer. In person, she was even better than any recording could ever be.
I weep again Whitney. RIP