I've had three dogs. The first one was the only one we didn't raise up from it's very childhood. I've got to say, a dog that you raise up from a little pup is the best one imo. Our first dog didn't have any problem with us because it was very peaceful and adapted to it's new family very fast, probably thanks to the good training their last owner gave it, but they couldn't keep him due to allergy issues.
The second one was a welsh springer spaniel http://www.gotdogsonline.com/welsh-springer-spaniel-pictures-breeders-puppies-rescue/pictures/welsh-springer-spaniel-0006.jpg that looked nearly exactly like this one. It had serious issues of being alone and we wanted a dog that really could manage on it's own for up to 8 hours straight. Our current dog, and the one who is very calm on it's own, is a black-brown hybrid dog that looks very terrying and big, but is friendly and calm and wouldn't hurt a fly.