Grammys 1988 defiantly, just for the power and emotion in Man In The Mirror. I like Motown 25 (it was iconic) but when you read Moonwalk and hear MJ's interview 1995 with Diane Sawyer, he said he wasn't happy with it and thats always in the back of my mind when I watch it. Also I think the moonwalk and toe stand at Motown 25 was properly his worst, but I think that was because he was nervous. I love the Grammys performance because MJ looked cool for TWYMMF, and that performance was amazing. But Man In The Mirror was just unreal, all the spins the emotion and his voice was so powerful, go listen to that performance then to LA 1989 (I know MJ was just getting over his laryngitis) and you will hear the difference and how clear his vocals were.