I am owned by a 10 year old Newfoundland named Picabo.
Newfoundlands are incredibly smart, docile and just know that the whole world loves them. She makes and ideal dog for a weekend warrior like me. Hiking 20 miles over the weekend and laying around during the week, is fine by her. She is extremely good with children, though she does tend to herd the smaller ones. She needs daily (short) walks and a run, but is otherwise low maintainance.
However, if you object to messes, you want a different dog. She can shake slobber at least 10' off the ground, she leaves black fur everywhere, and she can carry an incredible amount of water or mud into the house when she gets wet.