Having seen a good many penises in both excitable and chill states...
Guys' anatomy there divides itself into two categories. There are show-ers, men whose penises are fairly large when flaccid (and these guys invariably seem unduly proud of it), and growers, men whose penises are nowhere near the same size when flaccid (and who often feel needless shame at it).
Show-ers grow far less than growers when presented with sexual stimulus, and the two groups tend to be about the same size when erect.
And representing the ladies' opinion, it really isn't about the size of the penis, especially its length. A long penis hits the cervix and her body's reaction is cramping very like menstrual cramps. Not sexy. An experienced woman might enjoy a partner with greater than average diameter, or not. But *all* the ladies like a man whose skills matter more to him than the size of his wang.