I am a diocesan priest in the parish of Cyrill and Method in the Archdiocese of Vienna, and a teacher at the Over at the blog Unam Sanctam Catholicam Boniface wrote an article The Battle Lines Have Changed, in which he puts forward the principal thesis that the primary division among Christians is not along confessional lines, but between those who profess a creed received through tradition, recognizing an external (definitively binding) authority, and those who do not. I don't agree with everything there, and would be disinclined to describe the one side simply as "traditional", but agree emphatically with the general idea. It brings to mind Ratzingers article Relativism: The Central Problem for Faith Today. And it is something I've been thinking about and brought up in conversations a number of times.
Within and outside the Catholic Church a great deal of energy is spent discussing the Church's teaching and discipline on the sacraments of baptism and Holy Communion, Anointing of the Sick, on marriage, divorce, contraception, homosexuality, clerical celibacy, ordination of women. Catholics disagree and argue about whether the Church is right or wrong on such matters, whether its teaching is infallible, fallible but right, or plain wrong.
These disagreements pale in comparison with the disagreement between those who accept the creed, "I believe in Jesus Christ, his Only Son" as defined by the Nicaean Council, or "on the third day he rose again from the dead" as taught by the Scriptures or indeed in any significant sense beyond that in which many other persons live on in memory. Points on which, of course, the Catholic Church is in agreement with Orthodox Churches and many other Christian denominations.