You're beginning to sound like a salesman, Sophie's Dad!!! You know I'm teasing. I think you are giving great advice on your breed of choice.
Actually, I think that any enthusiastic, energetic dog will do. I have a fast, enthusiastic Golden Retriever....but I have learned through agility training....this only works in our own backyard and on Honey's terms. She has completely failed at agility. Her tail stays between her legs and she refuses many of the agility props, especially the tunnels and chutes. I've decided I'd better accept her like she is, and just keep her here, and anything we achieve is progress.
Good luck with your choice!
Logan