Oh, how I love this book. I loved this book when I was a child, and my parents, incredibly, actually took me to Chincoteague so we could see the ponies swim, and oh, I still can't believe how lucky I was! It was magic.
I've been almost scared to re-read this one, afraid that it would lose some of it's goodness, but I can say that it didn't- I still cried at the end, probably a good 20+ years after I read it the first time.
Best horse book ever, for me- knocked Black Beauty and Black Stallion out of the water entirely. Black Beauty was too Victorian-miserable and Black Stallion was just too... eh.
Misty was the horse for me, and still is.