As with many thing dealing with religion, things are up to interpretation. Labeling can also give an image of what is correct, thus labels also yield power. So which interpretation of Islam are we going to empower and label as the true Islam, the violent or the peaceful?
Here are a few a quotes I have seen to "prove" Islam is a violent religion.
Sura 9:5 "So when the sacred months have passed away, then slay the idolaters wherever you find them, and take them captives and besiege them and lie in wait for them in every ambush,..."
Sura 5:33 "The punishment of those who wage war against Allah and His apostle and strive to make mischief in the land is only this, that they should be murdered or crucified or their hands and their feet should be cut off on opposite sides or they should be imprisoned..."
Sura 9:73 "O Prophet! strive hard against the unbelievers and the hypocrites and be unyielding to them; and their abode is hell, and evil is the destination."
Sura 8:59-60 "And let not those who disbelieve think that they shall come in first; surely they will not escape. And prepare against them what force you can and horses tied at the frontier, to frighten thereby the enemy of Allah and your enemy and others besides them, whom you do not know (but) Allah knows them; and whatever thing you will spend in Allah's way, it will be paid back to you fully and you shall not be dealt with unjustly."
Sura 5:51 "O you who believe! do not take the Jews and the Christians for friends; they are friends of each other; and whoever amongst you takes them for a friend, then surely he is one of them; surely Allah does not guide the unjust people."