I'm partial to the Australian Shepherd breed, as I have two myself. They are super, super sweet and gentle, but I put a lot of work into them at first to make them that way.
They have Miniature Australian Shepherds that have all the benefits of Aussies, with less energy and are somewhat smaller. They make great pets. I will never own another breed!
I make it a point never to recommend border collies to people who A) live in city limits and/or B) have children. Border collies, IMO, make fantastic dogs! But to keep them from being destructive, they have to have either a real job to do (farm work, service dog, etc.) or someone who will spend almost all day every day pushing the limits of their minds. A border collie will quickly become the suburban family's worst nightmare in terms of manners, because there's just not enough for them to do. It's a shame to see such brilliant dogs being in pet-only homes, causing their owners grief. But that's my own personal opinion, and there's exceptions to every rule.
Honestly, I'd make a list of dog breeds you like and find a mixed breed puppy who has the traits of two or more of the dogs you like. A beagle/border collie (like my husband's dog) or an Aussie/golden retriever mix would be a good choice. You'd get a dog that has enough energy to keep up with kids, but not too much energy, is gentle, but still watchful, not nippy, intelligent, and easy to train.
Maybe a breed whose characteristics you like mixed with a poodle? A labradoodle, goldendoodle, or other such mix?