Many people tend to believe that many religions are just different paths to our Creator, and we just choose the path that feels like ours. I can't agree with that, never could. If we trust Christ, we have to trust His every word, and here's what...
"Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by Me." (John 14, 6)
Those underlined words are what causes me to disagree. He's not one of the ways, not even the best of the ways, but the only way.
On the other hand, we can see traces of the same Wisdom in different teachings - in Buddhism or Hinduism, for example, just like in Judaism. Why is that? I feel, just like Romanos wrote recently, those are just different versions of Old Testament, given to different peoples according to their context and culture. But Old Testament is not enough for salvation, it's more of preparation to the Real Thing, or words of advise on how to "survive" until the Real Thing comes in.
I also heard an opinion that it's nonsense to preach Christianity to, for instance, Buddhists, since their beliefs existed long time before Christianity was born. Well, the same could be said about Judaism. But again: those Old Testaments were not enough, even though they are huge, definitely not man-made. Yet, Christ is needed to complete the healing of the human's separation from its Creator.