I recently read a posting from one of my pastors regarding the exclusive nature of our faith. I would highly encourage you read this posting in its entirety here: Swallow the Pill of Exclusivity
Christianity is particularly controversial, just as the world today does not like the concept of absolute right and wrong, the Bible calls people out on their sinful nature and that very fact is unpleasant, and therefore controversial. I am glad however that Christians are charged with promoting the gospel, preaching it to others in a spirit of lovingkindness.
I think its important that we as Christians get our head around this concept. Our God is not an inclusive god. Take special note of how Peter responds to Jesus' question in John 6:68-69. Peter understood well that there was no other source for eternal life. It is Christ who holds the power over sin and death, and it is Christ whom we are to serve if we have any hope of salvation. That is, we take on faith what has been written about a perfect man that was fully God and fully human, who fulfilled the law to the letter, died a sinners death, and rose again, conquering the power of sin and death for all time. It is only through Jesus, by God's grace that we are saved, that sounds pretty exclusive to me. So go out and enjoy that exclusivity, but never forget your charge to preach the gospel to all tongues, tribes, people and nations.