The best performance I've ever seen has been Sufjan Stevens.
Simply incredible, the costumes, the graphics, the songs, the most fun I've ever had at a concert. AGH!!! BALLOONS. I LOVE BALLOONS. The Age of Adz is one of my favourite albums ever.
PLEASE. PLEASE. PLEASE. CLICK THIS LINK
HERE for all the photos of his London show.
http://www.youtube.com/watch?v=WZUCjXdfOQc&feature=related
Impossible Soul is 25 minutes long (this video is 9 minutes) so skip to about 1:30 for the BALLOONS. BAAALLLLLOOOOOONS!