Christianity is unique among the world's religions in many ways. Obviously the points are mostly faith based and could be debated, but that's the nature of faith...

For one, Jesus is the only one to have PERSONALLY claimed divinity.

Jesus is the only one to have died and then have been physically resurected before ascending to heaven.

Christianity is about God reaching\seeking out to fallen man. Other religions are about fallen men trying to reach\seek out God.

Here is a little more high level info on other world religions to help contrast the differences:
Generally Buddhism does not believe in a personal God or a divine being, it does not have worship, praying to, or praising of a divine being (although some sects do.) It offers no form of redemption, forgiveness, no heavenly hope, or a final judgment to those practicing its system. Buddhism is a moral philosophy, an ethical way to live for the here and now of this world to gain the ultimate state. It has more in common with humanism and atheism than its original religion Hinduism it separated from. But Buddhism is not atheism just because they don’t believe in a personal God. It is more like pantheism, there is a impersonal force the void which is the ultimate.

For Judaism, Christians beleive Christ is the messiah as fortold in the OT. Christianity is the fullfillment of God's plan as outlined in the OT. Jews today are still waiting for their messiah since the religious leaders in the time of Christ felt their power and prestige threatened...
More on how Christ fullfilled the OT:http://www.letusreason.org/Juda2.htm

.... I could go on, but just wanted to get the main ideas accross...