@farmerman,
a coupla dogs I would NOT recommend for families are those of the terrier breeds and a few others
Staffordshire terriers, Bull terriers, American Pit bulls, Tosa Inus,Presa canaries. Dogo ARgentinos,cane corsos and, believe it or not GERMAN SHEPHERDS. the overbreeding of German Sheps (and in some cases St Bernards) has resulted in a dog with many medical problems (dysplasia, kidney ailments, deafness, etc) and, they've become biters.
Ill bet, in the US, there are more attacks by german Sheps than pit bulls.
We have all these damned puppy mills that are progenating genetic some of these antisocial animals.
Still, by most standards of just pure devotion and pack identity, a mutt is your best companion.