In all honesty I've never understood the fascination with large breasts and the majority of men I've talked to who are "into" them seem shallow and superficial as that is all they seem to focus on, the big breasts of the "chick" or "broad" they are dating. Personally I don't want to attract those kinds of people anyway, particularly in the male gender as they seem to often only care about looks and think very little of the woman attached to those looks. If I end up with a b I will be more than satisfied. Gravity does bad things to the body as a person ages, so to me the smaller the better.
Also cup size is relative. It's nearly meaningless. A 34C for example will actually be a smaller cup than a 38C. The size of the bra depends on the actual size of your breast in relation to the girth of your chest. Consequently the cup of a 44B for example will be much larger than the cup of a 34B.
Basically focusing on bra size is pointless; as long as your breasts are proportionate the cup size itself isn't what matters.