I'm gonna go with Brad Bird I think on this project, but I still think it's worth noting Don Bluth here on my blog at least.
First off, looking through the works Bluth has done, while many were less successful animated films at the time, they were definitely the movies that made up my childhood. Rock a Doodle, The Land Before Time, All Dogs Go to Heaven, Anastasia, An American Tail, The list goes on and on!
What's even more interesting about his works, are how he came to making these films. Most were created after he left disney along with a bunch of animators who were unhappy with disney's subpar animations at the time. Disney sub par? I can't even imagine that, but I guess every company has to have there ups and downs!