As I recall the History Channel had a show on the Battle of Crecy(hitler was not involved strangely enough). They performed tests which concluded that the English longbowmen's arrows couldn't actually penetrate French armor. They then brought in a crowd control expert who studied the landscape of the battle and thought it would represent a serious crowd control problem. They were fighting in a valley and all of the French knights were going after the same few British nobles. The History Channel then looked at how the saturated ground affected troop movement. The effect of the mud was so bad that it required something like 30lbs of force for a fully armored French knight to pull his boot out of the mud. The much lighter armored English longbowmen did not have this problem. They concluded that the French had serious crowd control issues that caused them to bunch and fall over. Unfortunately for the French, due to the suction generated by the mud+heavy smooth armor contact, the French knights became exhausted and stuck in the mud. At this point the English longbowmen just walked around and slit all of the noble's throats as they received nothing for a ransom. Its been a while since I've seen that episode so I probably have a few "facts" wrong. The History Channel has seemed to have moved on to end of the world garbage
On another note, the Pope outlawed crossbows for some time because they were so devastating. I think its very clear where I stand in the crossbow vs. longbow debate.
Edit: wow this post is 15 pages long. I thought it was 3 pages...