One of the greatest misconceptions is the idea that all religions can be reconciled and brought together. I've seen the idea that since Christianity, judism, and Islam all worship the God of Abraham they can be brought together multiple times in this thread. The greatest problem with this is that while all three do seem to worship the same God, they are radically different and mutually exclusive in how you end up with eternal life with God/in paradise.
AFAIK Judiesm holds the belief that people sin, sin seperates them from God, but through Sacrafice and following God's laws this sin can be forgiven (or at least that's the way it was before the time of Jesus, I don't claim to know what their beliefs are today). Christianity believes that Jesus came to earth and his death removes the need for any other sacrifice, and that all anybody needs to do to recieve eternal life is to ask for the forgiveness that God freely offers that can come only from the sacrifice of Jesus. Not only that, but there is absoloutely no other way to be forgiven and recieve eternal life ("Jesus answered, "I am the way and the truth and the life. No one comes to the Father except through me." - John 14:6). Islam (again, AFAIK, this is only what i've gotten from what i've read/heard from various sources) has the primary pillars of faith (5 IIRC, feel free to correct me if i'm wrong), and if you faithfully follow those pillars and the other laws of Allah you will recieve life in paradise as a reward.
SO here you have 3 different ideas about how you recieve eternal life from the same God. While I can't say what Judiesm and Islam have to say about the exclusivity of their respective versions of how you get to heaven, i do know that the bible repeadetly states that the one single way to heaven is to recieve the forgiveness that God freely offers, and that forgiveness can come only from the sacrifice of Jesus Christ.
If we function under the assumption that one of these three is correct (even if only for the sake of this argument) then it's obvious that the other two are wrong, meaning that bringing the three together really means that every member of the two wrong faiths converts to the one true belief. Alternativly we could assume that all three are in their various ways correct. This however, this would mean that in all three cases there have been enormous misinterpretations/mistranslations of the bible/torah/quaran to get to the point where the bible repeately says that Jesus is the only way to heaven, while the quaran says that Jesus was simply another prophet of Allah, and not the savior. Given that case one is unrealistic at best (since the root of all disagreement between the three different religions is the question of who is right), and that option two is realistically impossible I doubt that we'll be seeing a unification of these three faiths at any point in time.