A ball is a great choice as are colubrids like milks, kings, and corns. I love the boids, hence the name, but my brother has a corn (that I take care of ) and they are interesting snakes as well, especially if you like the colors of them.

Are you looking for a snake that reaches no longer than 5-6' necessarily or what are your 'requirements' for a snake. Colubrid or boid?