Having grown up with dogs, my parents had two German Shorthaired Pointers when I was born, so literally all my life. My best advice to you is, pick the dog that fits your lifestyle and family. Meet with the dogs, get to know them, you don't have to take them home right away and any shelter worth it's salt will let you come back and visit the dog, take it for walks, meet and talk with the dog's handlers.
Pick a dog that will match your energy level, do you stay home most of the day and only go outside a little bit? Get a dog that matches that engery, or are you extremely active, outside all the time going here and there, can't sit still? Get a dog that needs lots of exercise. Don't get a lab if you are going to be sitting in the house most of the time, that breed tends to need more room to run and excercise. But on the flip side if you have an active outdoor family getting a dog that just wants to lay about all day is also a bad match. And you can't always tell by the breed how much or how little energy the dog will have, breed does play a part but dogs have individual needs and personalities, which is why I say get to know the dog.
Sometimes people at the shelters don't always have the best advice. You know what is best for you and your family. Also if you are really unsure of a dog but want to get some more experience with the dog, try fostering it for awhile and see how it goes. I am not sure about where you are, but contact local rescue groups and see what they have to say, some have puppies and older dogs as well. There are rescue groups for all different kinds of breeds and some like the one I foster for, we foster everything.
I was a foster home for dogs and will be again once we move, and we own two of our own, a 6 month old black lab and a 5 year old terrier mix (a toy breed at 7lbs) I have two girls, a 3 1/2 year old and a 19 month old. My neighbor is also a foster home for dogs and we work closely with our organization to place the dogs we foster, lets face we love them but we can't have them yo-yoing back all the time. There isn't one breed that is perfect for a family or not. Our last foster dog, was a pit bull mix and she was as sweet as can be, great with the kids, even let my 19 month old ride her and played with the neighborhood kids. She went to a home similar to yours and they tellm e she is doing great. So dispite what you might hear about this breed or that, negative or positive, it isn't always true.
If you need any more advice or help or have any questions feel free to send me a message, I am always willing to help people find the right dog for them.