heum, bewawolf19, we can do exactly the same thing. (But, about the crusade, the most important reason isn't greed, or something else, it's about to occupy mercenaries, and the too many young adventurous and landless noble at time of peace (in europe).
The muslim Jihad was decreed after the beginning of the first crusade, (unless you consider the islamic expansion which was not considered at the time as a jihad, but it is a little dishonest to take something so old). And about the treatment of non-Muslim populations by these, well, Christian do worst thing and where less tolerant.
Crusades were also opportunities for Muslims to change many things in their local politics, shifting alliances etc.. (i.e. as Saladin). War is always a bad thing's, but it is also an opportunity for some people to create peaceful meetings and exchanges (spiritual, political, ...) between two cultures. This is what happened during the Crusades, if you read, you will discover that there were some massacres, some battles, but also a lot of mutual borrowing(?), discussion and exchange.
By the way, say there is a bad and a good side is something improper in history. There never been bad and good side. Some Crusader do that with strong belief in their faith, some others only greedy or violent reason, some where lure by official speech, some other had political reason to act like that, some just defend their family and land (in both side, because, when you are in a besieged city you have to defend). And in both side, that's the same thing.
Also, i really love Vicking Rock!
that make me laugh for a while!