Should I get a border collie or an Aussie?

I'm looking for a high energy dog that can run with me. I am also looking a bit into agility. People say these dogs have alot of energy and are really smart. I may end up moving to an apartment. I would take them for long walks everyday. Also which one is more of a Velcro dog? It would be really helpful if you could list the average price. I would adopt but I'm looking for a dog with papers. AKC registered preferably. My family currently has two dogs which are my brothers. I'm looking for more of a one person dog. If you could help me I would be overjoyed. No rude comments about playing with the dogs we have. I do but they are my brothers dogs and ignore me as soon as they see them.