I've probably posted this before, but it can't be denied. Queen's appearance at Live Aid is one of the greatest festival concert performances ever. The connection with the audience at Wembley is emotional and true. Freddie Mercury embraced them. and they back.
I can also present a valid argument for Otis Redding at Monterrey. It's a good argument to be able to have. Those are my top two, in no particular order.
Any others? I'm sure there are. I'm thinking of a few now. Something from Woodstock? Radiohead at Glastonbury?