We have decided to add a dog to our family. I'm very open to breed, happy with mongrels, but as a first time owner I'm not keen on an older dog from rescue in case it has suffered experiences I'm not able to handle. We have two cats and three young children and have ruled out Greyhound /Lurcher types, Staffs, any micro breeds and I don't think super-active collie type dogs would suit. We have a large garden and I'm home all day so it will rarely be left alone for long. Secretly I'd love a St Bernard / Newfoundland but I'm worried about possible health issues. What types should I read up on first that might suit?