I have a few muslim friends and I've spoken with them in regard to the whole "kill the unbelievers" thing in context of "eye for eye" and other things... What they told me is that Islam indeed teaches that, however it also says that if you forgive the unbeliever instead, you will be graced by Allah more than if you'd have killed him. Now that I read it, it sounds kind of cheesy, but that is the best I can do translating what they told me to English.
They also said that this whole violence is caused by misinterpretation of the scriptures. Which is probably true. I have no islamic experience at all, so I wouldn't know.
Religions should not be taken lightly. It is all-or-nothing principle. Faith is not a chinese buffet where you pick what you like and leave the rest. You either accept it all, or not at all, otherwise you're but a mere pseudo religious hypocrite.
Now regarding Judaism. I know first hand that it teaches that "goi" or non-jews are less that human. "A jew is above all other peoples as those people are above mere animals" - again translating to English from Kitsur Shulhan Aruh (probably didn't spell it right). I also know that the 10 commandments do not apply if the crimes are made against non jews. How do I know? 4 years in kosher catering teaches you something. Especially when the rabbi tells us that we are animals and not human. I also did some reading as well. Most jews do not follow this teaching to such fanatical extremism though. Although I saw with my own two eyes how a group of jews started spitting all over a priest who was just passing by. He literally got covered by it. That was in Jerusalem. Don't believe me? Oh well, what can I do? You only have my word for it. Now that I think about it, in my months in Israel and Egypt, I never had problems with Arabs... well some kid tried to rip me off, but got hit with a newspaper by a nearby standing man, and came back and gave back the money. By the way, I am a member of the clergy as well, so the above said incident is really painful to me.
Christianity. I am a christian, belonging to one of the "super traditionalist" orthodox churches. The official churches do not like us because we criticize them - pointing out their deviations from the teaching. For that, they heavily prosecute us (especially in Russia, even right now), displaying true christian love (taking away or burning churches, beating the clergy, stabbing/beating/abducting of bishops and other acts of love). In my short years I've seen terrible terrible things from christians. They gave me more sorrow than anyone else. You cannot even begin to imagine the corruption of people who call themselves christians, especially in monasteries (i lived in one for 4 years, but no, I didn't see anything gay. I saw everything but gay there actually). However that did not shake my faith. I still believe what the orthodoxy teaches. People are corrupt, not the religion.
Of course if you start picking things out from christian teachings you could end up with "Judah went and hung himself" "So do you in my memory" "And thus you'll inherit the Kingdom of Heaven"
When you start picking out things you like and dislike, it just goes downhill from there.