I am tempted to write “name, street address, city, state or country”. Not to mention (@Gog) that I personally would not like to called a so-and-so.
Seriously, these are matters are dependent on minhag. In some countries one only addresses personal friends by first name or singular “you”. In Russia one uses the first name plus the patronymic (e.g. Vladimir Vladimirovich). In some countries (Israel, for example) not using the first name is a considered stuffy. I definitely would not go by popular halacha books as first of all they tend to be as machmir as possible and then some so that they will not be attacked and secondly they reflect the author’s particular community even though they purport to pasken for all Jews.