I think there's a lot of "smart breeds" what about the terriers, like jack russell or fox terriers?, in my house Tabatha is condisered the most inteligent cause she can recognize a lot of words, but every member of my gang show his inteligence on his way. Diesel just had two accidents in the house and now he wake me or my wife in the morning for go out and do his bussiness. Lola is so smart but uses her inteligence just to satisfy her needs and she has been the most hard to train, she loves to ignore me.
But if you talk about training for agility or obedience, a task that all breeds cand do it, yes i have to go for the Border Collie.