For most women, anything above 7 inches is too big, and will only result in pain. 5 inches may be slightly below average, but is sufficient to satisfy.
That site linked to above with the stats is not exactly a Mecca of objective information on penis sizes, as they sell PENIS ENLARGEMENT products.
Most studies I have heard of say 5-5.5 inches is the average for Caucasian men, and slightly larger/smaller for other ethnicities.