I have to agree on size doesn't necessarily matter. It is your ability to use it well. However, a nice girth is always nice. I would like to be able to at least know when it is in, or not. ;) a man can be 4 inches in length, but if it is 2 inches around sex for him will be good. His short penis will most likely be able to hit the g spot more often than a man with a long penis.
My first husband had a big penis. I would say close to 8 inches, or more, with a nice girth. However, sex with him never really felt that great because he didn't know how to work it.
My second husband was around 6 and a half inches, and almost 2 inches in girth. Sex with him was good, but only after many years together and him learning how to please me through clitoral stimulation. While vaginal intercourse with him felt good sometimes, he would also sometimes hurt me when he thrusted deep, because he would hit my cervix.
My current and final husband is average length and has a small girth. However, with him, vaginal intercourse feels wonderful, because he knows how to work it. With him being shorter he never hits my cervix which can be very painful to a woman. He can thrust hard, which feels great, and he never hurts me like the other two did. Although we are still working on learning how to please each other, I would have to say that vaginal intercourse with him is the greatest I have ever had, even though he may be one of the smallest men I have ever been with.