@Crazy Anglican
Yes, off topic, but given the state of this thread I don't see the harm in going there.
Essentially the division between the Catholic Church and the Orthodox Church is nothing more than politics. The same differences existed before they parted ways, but none of the huge problems they supposedly have now existed then.
For the record, the two groups didn't actually split in the 11th Century, as most say - the individual who was Patriarch of Constantinople was excommunicated by a group of (three I believe) Cardinals following the death of the reigning Pope. That's obviously not valid from the current Orthodox or Catholic point of view and certainly wasn't valid then (when the Roman Patriachy held primacy but Constantinople was second in like as far as the five Apostolic Patriarchates were concerned - meaning only the Patriarch of Rome could excommunicate the Patriarch of Constantinople). In response to that excommunication (which I might add the Cardinals delivered on the altar of the Hagia Sophia during the pre-liturgy rituals, violating the sacred space of that church) the Patriarch of Constantinople excommunicated the Pope since the three Cardinals were supposedly doing this in his name, despite the fact he was already dead (nb: this whole scene saw two individuals get excommunicated, not their offices or anyone else under their authority).
That said, the split between the Catholic and Orthodox Churches occurred in the 1400s, after the capture of Constantinople by the Ottoman Turks. The Turkish sultan basically told the Patriarch of Constantinople and all the bishops under him and in Muslim territory that they had to break with Rome or die (plus the sultan gave the Patriarch of Constantinople the title "Ecumenical Patriarch," which the Constantinopolitan bishops had been trying to get from the Byzantine Emperors for quite some time).
Given all that, the only real difference of theology between the Catholic and Orthodox Churches at this point is over Petrine Primacy. From the interaction between Jesus and Peter in the Gospels (the "on this rock I shall build my church" and the giving of the Keys of Heaven to Peter) the Catholics claim to have proof of the unequaled primacy of the Petrine See - the Bishops of Rome is the indisputable earthly (obviously not total) head of the Christian Church in their eyes.
The Orthodox Church, on the other hand, purports that the relationship between the Roman Patriarch the rest of the Christian bishops has always been "primus inter pares" Latin for "first among equals". That is to say, the Orthodox hold that the Petrine bishop is indeed first among all the bishops, but that he is still basically the bishop of Rome and Patriarch of the West. Think of it this way: the Catholic Church sees the Pope as the a chief executive - everything in the church is his business; the Orthodox Church sees the Pope as the ultimate authority in his jurisdiction and as having a sort of appellate jurisdiction outside of the Patriarchy of Rome.
What amazes me is this was never an issue until after the two groups split. Until then they seemed to get along fine as far as being one church was concerned - though there was certainly always a great amount of cultural and political strain between East and West. However, things like the Filioque controversy and the Assumption/Dormition of Mary and the Immaculate Conception of Mary are all non-issues (i.e., both churches have the same teachings on those issues essentially, they just word their teachings differently and that's always been the case, since time immemorial).
In other words, they're basically two bratty siblings fighting - they're still in the same family, they just don't want to acknowledge each other. Also, please note that Catholics and Orthodox Christians are allowed (under duress) to receive the sacraments from each others' clergy (that is to say, if you're going to die and you're Catholic an Orthodox priest can administer confession and last rites and vice-versa - both sides agree on this, they just aren't "in full communion").