What are the most powerful renditions anyone has heard of this crucial section to the Appassionata Sonata?
Without doubt, the most powerful (and certainly the fastest) I have heard is Emil Gilels account. Other particular codas that come to mind include Sviatoslav Richter's various live accounts and Rubinstein's studio recording.
Personally, when it comes to this coda, I think the faster the better (Perhaps just a happy coincidence that it is Gilels!) and the only one who can pull off the slow approach successfully is Claudio Arrau. (http://www.youtube.com/watch?v=bdACFlwKpvY)
Incidentally, Arrau does actually go a bit mental in a live recording I have, and I've attached it at the bottom. He really goes hell for leather into it, and nearly f***s it up, but actually pulls it off. So does anyone know of other recordings that really take the Presto indication to heart?
If you want to see a strange (and for me very disturbing) coda watch Fazil Say's Appassionata (at some japanese recital). While i think he did the rest quite ok he plays the Coda in super slow motion. My favorite recording is Gilels but i personally don't think he exaggurates in terms of velocity.