To go off on a little tangent here, on my way down to check out St. Vincent Ferrer Church in NYC (truly magnificent), we drove by the Ukranian Catholic Church in my neighborhood, with the ubiquitous Orthodox Church acrosss the street. What I found odd was that the Catholic one was round and looked very "Orthodox" (or at least my idea of it), and the Orthodox one was simple, brick, and somehwat Protestant looking, except for the onion dome on top. Just thought that was interesting for no particular reason. Still would like to visit both.
Oh, Byzantine architecture does give you a sense of mysticism -- if you ever come to London, do check out Westerminster Cathedral -- it is impossing and very very Byzantine -- icons and vaulted ceiling and unlit yet holy places. It kind of makes me imagine what a mass in the Hagia Sophia would have been like.