Check out the article, why I’m not Eastern Orthodox, I believe it’s on Catholic answers site. I think the problem with debating folks from Eastern Orthodoxy, is that we have so much in common. I think another problem, is what someone who is a practitioner of Orthodoxy believes, may depend on who their Bishop is. I had a friend of mine, I was talking to, and he was telling me about a friend of his, that was becoming Orthodox, and saying that he had to be charismated (sorry if I misspelled that), even though he’d already been confirmed. That really does depend on who his Bishop is, other bishops wouldn’t have required that. Some, although not all, may have said that he was not even validly baptized. When you talk to someone that is Orthodox, always bring back the issue of authority, but you need to start out with what you have in common. By the way, lest I forget, Dave Armstrong has articles on biblical evidence for Catholicism blog, that deal with Eastern Orthodoxy. I had an instance where I had an Eastern Orthodox priest as a professor, that defended the position, that the Catholic position on contraceptives isn’t infallible, obviously I disagree, however, he was very defensive, when he was talking about Catholicism, and he flat out said that he was frustrated with people saying Catholics worship Mary, he said they give her honour they give her respect, and there’s a place of common ground right there, the Orthodox hold our lady in very high reverence.