Jennings was, of course, amazing but I always think of him as more of a contemporary to Best than having come after him. He was a year older than Best. Though he did end up playing top flight for about 300 years, didn't he?
He was a bit of a c*nt as a player, but I'd still put Keane ahead of Brady, personally. Though, maybe I put more weight on Keane's brilliance as Brady's best years were before I was born. I remember as a kid loving Keane at Forest and hoping Liverpool would sign him.