So, I begin to suspect that part of the problem between Catholicism and Orthodoxy on original sin involves baptism. Bear with me, because this is a thought I just had, so it may or may not be coherent to people who are not me at this stage. :)
I've heard baptism described (in Catholicism for Dummies) as a vaccination - but I don't know that that analogy really works. When you get vaccinated, you don't get the disease that you're vaccinated against. Yes, the Flu Shot seems to wreck my issues with this, until you recall that they're about a billion strains of flu, and the Flu Shot only vaccinates against the ones that are felt to be the most prevalent that year. Think more like polio, etc. People don't get those anymore, in places where we vaccinate for them.
So, baptism as vaccination, if we carried that analogy, once baptised, people wouldn't 'get' sin. Clearly, that's not what happens. Though I suppose, now that I've typed it out, the Flu Shot analogy *does* work a little better - baptism only vaccinates against a particular 'strain' of sin - original sin. *However*, as I have been assured by other Catholics, and the Catechism, the Catholic Church teaches that we don't actually inherit the original sin. (I have a bit of news for them, in that apparently most people -including many Catholics- think that the Catholic Church *does* teach that...) In that case, the vaccination analogy *still* doesn't work, because you're vaccinating for a disease that doesn't exist anymore - it's impossible to catch it.
And it's also not like some giant 'reset' button, because if we don't inherit original sin it doesn't wash it away, and it certainly doesn't undo the inherited consequences of original sin... so what, exactly, does baptism do?
I still think baptism makes the most sense as 'circumcision of the soul' - the sign of the new covenant, bringing us in. Baby Jews are circumcised, and also adult converts (which, ouch, you know?) and, in the case of the babies, there's not this 'believe first' element, or they'd wait until the children were older to do it. Instead, they're circumcised, which brings them into the covenant, and then expected to live by it their entire life. They're brought up observing the Law. So, you know, that makes sense to me.