According to St.Paul, we're born "children of wrath." While there is certainly an ontological reality behind such "legal"/judicial language, the statement obviously stands. I think too often people are trying to articulate the Orthodox stand on this topic (and on many others) in contrast to something else. Well, that's no way to live - in comparison/contrast to others.
People most certainly are born into sin. They are not what they are supposed to be - they're in a contra-natural state (via natural generation/birth) in which they're pre-disposed to keep on sinning, and it's a state which is not pleasing to God. Christ reconciles men to God in "two directions" - by raising to God a sinless humanity, and offering His obedience as a man, even unto death - and by making possible the divization of human nature in the fullest degree, and making me members of Himself. The word "sin" itself refers to "missing the mark" in the Biblical Greek language. So obviously, being born graceless and in rebellion (goodness having to be added on later, in particular the grace of the second birth, in Holy Baptism), one is in sin.
Yes, obviously this is different than personal guilt - but then again, I'm not quite sure just who teaches that infants are born with this type of "guilt", so to speak. Very often I hear people saying this is the papist teaching, but I can say quite certainly it is not. Thus, I'm somewhat at a loss...perhaps this caricture of things is taught by some Protestant groups, as it does smack of the coldness of Calvinism. Or perhaps it's a perception based on popular piety, which I find in the west (such as in Roman Catholicism) often does embody a lot of the cliches which Orthodox Christians believe/sense are true of western heterodoxy, Roman Catholicism in particular.
As for the Mother of God, Orthodox do not believe She was conceived "immaculatly", precisely because it's not true. It's not because on this point Orthodoxy has some completely weird, esoteric, mystifying teaching on this topic that is radically different than that offered by Papism - Orthodoxy simply doesn't accept the idea. Our Lady was born mortal, and fallen just like everyone else. That She never sinned (certainly not grievously), and that Hers was a life of providence from the earliest stages, is quite different than insisting that She is somehow just shy of Christ in Her make-up as a human being.
A big problem with the "Immaculate Conception" (I.C.) position, is that it basically requires one of two completly unacceptable possibilities...
1) the Mother of God never died (which the Church's Tradition makes abundantly clear did in fact happen - that this just kind of got forgotten by the Latins, is only evidence of their lack of catholicity and shortness of memory on many important topics)..
2) the Mother of God did die, but this was a choice of Her own, much like Christ Himself (which smacks of the "co-redemptrix" heresy, also popular, understandably, in Papism.)
Christ was free from sin. He was free from original/ancestral sin. That He died, that He even experienced the non-blameworthy passions and could taste the bitterness of sufferings (which are not experienced by even the Saints when they're in the state of theoria) is the result not of His simply becoming Incarnate, but rather by His decision - He humbled Himself, not in simply becoming a man, but in becoming a man of great meekness and suffering. This is the kenosis spoken of by St.Paul.
The I.C. "dogma", if it recognizes that the Mother of God did in fact die, requires one to believe She somehow "submitted" to death, in parallel to Christ. This is simply wackiness, and completely out of the blue.
Unfortunately, many Roman Catholics are sorely misled (mainly by their apologists), because the term "immaculate" does appear for the Mother of God in many Orthodox prayers. Of course, what is left out is that being "immaculate" (by ascesis and grace, culminating in the great grace of becoming the true Mother of God) does not equal "immaculatly conceived" or anything like this.