I'd agree Michael Lee was an immense talent, I remember when he first started riding for Kings Lynn, the media was giving him huge wraps, I saw him do amazing things on a bike.
Ronnie Moore was before my time so can't comment there, although I've read about his comeback, to do what he did would take something very special indeed.
Kelly Moran was also incredible on a bike.
I'll throw another name into the hat..Jan O Pedersen.