Prior to the Crusades though, much of the more important Moslem/Christian interactions actually came from the Norman (yes, Viking) ruled island of Sicily and the heterogeneous intellectuals of Spain. Both Jewish and Moslem scholars had already been translating Greek and Arabic literature from Iberia into Latin and Romance languages for commentary and criticism, and the important Scholastic movement had existed before Jerusalem's 'reconquest' was even considered. This is not to say that the seizure of Classical material was completely beneficial. The manner in which intellectuals of the day held onto Ptolemy, Aristotle, Plato and Hippocrates well into the Renaissance caused many problems, and the latter half of the Middle Ages owed more to original and critical philosophies such as Humanism. Keep in mind that ancient Greeks had a very poor understanding of medicine, but also keep in mind that this did not stop Medieval doctors from bleeding their patients to balance the non-existent humors of their patients all the same.
Though the period saw a surge of Classical interest, many of the Europeans had very little idea what the Roman Empire really was (for instance, often ignoring the fact that the Empire was actually in Constantinople), and many tended to exaggerate how much they actually owed to the Romans and Greeks. Medieval Europe had a larger population, and boasted original accomplishments in established sailors, superb theological universities and superior metal-smiths whereas the Roman Empire did not have any of these. That they also fanatically held onto Geocentrism simply because Ptolemy promoted it, however, is very telling.
Even with the Crusades, the actual importance of Jerusalem to culture is also exaggerated. The metropolises of Alexandria, Baghdad and Cordoba were far more valuable as a whole, and Alexandria in particular had been the true scientific capital of the world since the Greek Ptolemaic dynasty was established in Egypt. Thankfully for early Medieval Christian philosophers, however, much of the Middle Eastern works had been widely circulated westward thanks to the Moslem love of libraries. To put that in proper context, even a single book was very opulent when they all had to be written by hand; a whole library full being quite priceless
The attempted conquest of the Middle East was mostly a religious venture in any event, and the long term, practical benefits of seizing Jerusalem were non-existant. Indeed, going on Crusade often meant most participants would endure irrecoverable poverty and the risk of dying en route (the most common cause of death, perhaps). The reality of the Crusades rang particularly true after the Italians' lost their trading ventures and were overshadowed by the economies of Northern Europe and unified Spain. Arab and Orthodox Christians remained hostile to a Catholic presence all the same, and both Balkan Pagan and Jewish communities domestic and abroad endured relentless atrocities. The Crusades had the opposite effect of securing the Holy Land in the end: The sack of Constantinople permanently weakened the Roman Empire and prepared the region for eventual Ottoman conquest.