In selecting our family dog, I used a book called The Right Dog for You, which assessed our family's resources, personalities, requirements and preferences, and showed the appropriate dog breeds with various physical and behavioral characteristics summarized in grids. We ended up with a Newfoundland, a lovely, gentle giant who tolerates our children beyond expectations.

I suggest that you get the book, or use a similar online service. Try this one:

http://www.poochpicker.com/