We haven't had any crusades but Europe is still soaked in blood between the various Christian denominations having a go at it. 30 years war, Hundred years war etc. That wasn't so long ago. The Catholics and Protestants in Northern Ireland are still taking a whack at each other from time to time.
I don't think any religious is inheritable violent. In fact most (including Islam) preach peace and tolerance. The problem as usual, is people who seek to dominate others and who twist religion to push extremist agendas on others. The fact is you can twist the Torah, Bible, Koran into saying anything you like and then justifying that through violence.
And BTW, I think in the USA some of the more radical evangelicals and Born-agains are a hairs breath from adopting violence and terrorism to push their religious interpretations. World Church of the Creator for example as been implicated in several hate-related attacks. Their leader got life in jail for trying to assassinate a judge. Since we don't have a born-again Christian Fundamentalist as President anymore, the loonies are going to start to feel disenfranchised, isolated, and persecuted (a.k.a war on Christians). Like all radicials, these people only view themselves as "Christians", not anyone else -especially not those who don't share their radical ideas.
You can be sure some of these people will adopt violence to put themselves and their twisted religion back into the spotlight. They are as radical, intolerant, and hateful as any Islamic group. Some of them are so loony that ought to be hunted in the same manner Osama is just as a precaution before they really do something crazy.