I am a b cup, but I would rather be smaller. Once you are past 30 or so, gravity becomes an uncomfortable fact of life. Small boobs don't droop! I have a friend, very slim, barely an a cup. She is close to 50 and still has the body of a teenager. I had another friend who was huge as a teenager, and even then jokes about having to dig them out of her armpits!
And not all men like big boobs (it's mainly the ones who have mother-issues, I tend to think!). My bloke much prefers small ones -- he thinks i'm a bit too lumpy, really.
I think part of the issue is that the only breasts we ever see are the "perfect" ones -- I have nothing against showing topless women in the men's mags, but they should be forced to show a random sample of the actual female population. I was stunned when I first started going to the gym, and saw the variety of women in the changing room -- it was hard not to stare. The variety is truly incredible.
The best blokes are really the ones that don't mind either way, it's whatever is attached to the person they love that's fine with them.