I do not relate collies with lower energy. Imagine walking into a house and having three giant wedge noses coming at you from all directions. Before you set foot in the door you are pinned. Then one grabs a toy and the others run for it. Two get into it over the toy and the other stands over them barking like crazy. Then they get under the table legs and knock over everything. This can go on for hours. Bring them outside and they need to run run run and chase everything in sight. This is the scene at my future uncle-in-laws house each time I go over there. These dogs are local obedience trial champs and yet this is how they are at home. They run the house, they bark constantly, and they don't loose any energy inside. I myself have never met a calm collie. As for wolfsoul saying the brains are bred out of them, its so true. These three collies are daft as they come, but they can put on a good show in front of a judge somehow. Sweet though and very loving

Shelties on the other hand I've met many. I've met sizes ranging from 12 inches to 20 inches. They bark a lot. I've met calm ones, and hyper ones. They seem more trainable. All the shelties I have met are yard trained and have some house manners. They seem much more calm in the house as compared to the collies I've met.

If you are looking for a clam breed though, I don't recommend either.