I'd say, quite a bit. I think, once they got past their own personal and religious biases, both sides were able to come to an accord of sorts and learn from one another. For instance, there are records that state that despite being sworn enemies, King Richard and Saladin held a great deal of respect for one another and behaved courteously to one another, despite being at war w/one another. Just one example, but I feel that this was much more commonplace than is recorded- I think it is this way because historians didn't want it be known that because of the war, two cultures collided and learned from one another; if that were so, how could the Crusades continue when it was realized that the Muslims didn't have to be our enemies had a meeting of the minds taken place FIRST.
Of course...war has always been profitable to the few who mastermind them...