Curt Jester has a good post titled Merry Syncretism in response to Bob Schieffer's "all religions are basically the same" speech.
I don't have much to add other than for me everything hinges on the promises of Jesus. Your religion is only as credible as your founder, and no religion has a founder as credible. And Christianity is arguably the only faith other than Judiasm that is comfortable with both faith & reason.
Finally, small differences in the conception of God make HUGE differences over time. So do seeming slight theological variations. Witness what the blogger Old Oligarch wrote:
"When the idea of 'rational sufficiency' first reared its head clearly in a Christian society, about the beginning of the thirteenth century, the Christian soul felt an immediate shock of horror, as faced with the concupiscence of the mind which was the completion of original sin." -- Henri Cardinal DeLubac... DeLubac was talking about the slight theological aberrations which encouraged the subsequent 15th century heresy of Louvain theologian Michel du Bay who basically claimed that unfallen man could reach beatitude without the assistance of grace. The whole book is a study of how late Medieval theologians are in part responsible for the genesis of philosophies which made atheism plausible for the first time in history. Well, that's actually a "byproduct" of the study, which is about a more technical issue in the nature / grace debate and the havoc it caused when handled incorrectly. It's the kind of book that makes you want to run screaming from the practice of theology, lest you screw something up and generate a monstrous ideology. DeLubac shows how many brilliant men with good intentions ended up having a hand, most unwittingly, in some devasting intellectual movements.