I'm new here, but I do have an insight on dog selection. Obviously any puppy is going to have boundless energy, that's a given. If you raise the dog by going on runs and exercising them, the dog will always look forward to it as the years go on and never not want to go. So breed probably doesn't matter. In fact, I would look at it more as which breed can you actually offer the right amount of exercise too. In other words "which breed can the human keep up with?" Dogs don't generally have the distractions that humans do i.e: jobs, children etc. so they are ALWAYS up for activity, and some require more than others.
Heres an example of what I mean: we had a rottie for 13 years. After getting through his puppy phase, he was just as content to lay around as he was to be active. He never really showed signs of being unhappy about being sedentary, but would always be willing to get up and play. Truly an awesome dog.
Now, we have a Boxer: This guy is awesome as well, but very different. He needs to play and run or the consequences are obvious. If he sits around for a couple days, he drives everyone nuts. Don't get me wrong, he can sleep all day and love it, but the next day, he better be able to burn off some steam or he will be a pain in the ass around the house. He has endless reserves of energy and can play / run all day long and still be ready for more, but he only needs about 1/2 hour - 1 hour of quality running / playing to be happy and less of a P.I.T.A. around the house.
My brother, who is an ironman athlete has a mutt type of dog with a lot of "labrador" traits. This dog is also a cardio machine. My brother will go on long training runs (marathons) in the woods and he says the dog runs off leash the entire time. The dog runs ahead of, around, behind, back-forth etc for the entire 26 miles. (My brother estimates the dog easily does twice as much mileage as him). That's crazy, considering that afterwards the dog is seemingly un-phased and ready to keep going.
Anyway, once you narrow down the breed, select the dog from a litter where you can actually see different character traits. If you want an active dog, select the most active from the litter. Mellower dog, mellower dog from litter etc.
I am never one to push "my way is the best" on anyone. So please don't take this next comment as that: You might want to learn more about the boxer breed. They are extremely athletic, love doing different types of agility and speed activities, and never run out of enthusiasm. Not sure of your family situation, but we have the toddler from hell, and the dog has an endless tolerance for the abuse commonly given from small kids. My daughter lays on him, pulls him, hits him (when we are not looking, of course) and he just lays there, never even seeming to mind. Occasionally she will sit next to (read: on top of) the dog, usually he just scoots over so she actually does end up next to him, but occasionally he just gets up and moves to the other couch.
Sorry about the ramble, hope this helps. Good Luck
edit: if you read up on the boxers temperament, you will find that they are not considered an aggressive breed what so ever, probably the exact opposite. Not that I believe any of the typical BS reputations about certain breeds, it's all in the handler, but a few breeds do present insurance premium surcharges. It's unfortunate that the wrong kind of people end up owning breeds that CAN BE TRAINED OR MISTREATED to become aggressive and destructive, which otherwise would be great dogs.