My wife wears a singlet top under her bra - possibly because an A cup is just a bit too large for her breasts but the singlet top helps to fill it up more.
i agree it depends on the person. just like everyone has different tastes in music, or food. there isn't some general answer. personally i wish mine were smaller.
i,dsay my wifes titties are average size just perfect for me could be a few sizes bigger but i aint complaining, hate massive titties