Peter Kirk has posted a discussion of the Latin text Augustine was familiar with and its effect on his doctrine of original sin. The claim is, effectively, this: Augustine believed in the doctrine of original guilt because of an ambiguity introduced by an excessively literal Latin Bible which persists in the Vulgate and later theologians have a propensity to read original guilt into the text of Scripture because Augustine did. The passage in question is the end of Romans 5:12. The English translations are pretty much all the same: "in this way death spread to all men, because all sinned." But Augustine's translation says "in whom all sinned." The English translations are certainly more accurate. It is true, however, that many theologians, following Augustine, have claimed that everyone sinned in Adam. For instance, Michael Rea's paper "The Metaphysics of Original Sin" (which I highly recommend, if for no other reason than because it's fun) discusses several Western accounts of original sin and finds it necessary to examine various accounts of personal identity, since some of these theories require that we actually each be identical with Adam at the time of his first sin, and not identical with him at his second sin, i.e. that in Adam's eating of the fruit we literally all sin in him.
Now, in the comments, Jeremy and others argue, and Peter concedes, that no contemporary Protestant theologian actually makes the argument Augustine makes and, in fact, have other arguments for this conclusion, but Peter nevertheless (plausibly) claims that we tend to be more inclined to accept this view because of Augustine's influence on the tradition.
Peter's claim is supported by the fact that in the Christian East, where Augustine's influence is considerably less (though he is still a canonized saint), theologians have generally accepted original sin while denying original guilt, which, if I read him correctly, is also Peter's view. I have been told that this view was also held by John Wesley who got it from the various Eastern Christian writers he read (he was particularly fond of the Macarian Homilies). The view is this: because of Adam's sin, human nature is corrupted so that none of us is able not to sin (Romans 3:23); however, contra Augustine, we are held guilty only for our own particular acts of sin (which we all necessarily commit due to the corruption of our natures) and not for Adam's sin.
Now, I see the doctrine of original sin as very strongly supported by Scripture, whereas I think the doctrine of original guilt is something that comes primarily out of systematic theology rather than the clear teaching of specific passages of Scripture. (Augustine, of course, had a specific passage teaching this view in his Bible, but that was due to a misleading translation.) In fact, Romans 5:12 seems rather supportive of the original-sin-without-original-guilt view under consideration as against the Augustinian view. For the record, I regard both views as plausible and orthodox, provided that those who deny original guilt make strong enough claims about depravity.
Throughout Romans 5, Paul sets up a parallel between Adam and Christ, the new Adam. "if by the one man's trespass the many died, how much more have the grace of God and the gift overflowed to the many by the grace of the one man, Jesus Christ ... from one sin came the judgment, resulting in condemnation, but from the many trespasses came the gift, resulting in justification." (vv. 15 and 16) And the correspondance is real: indeed, there is a theological debate directly parallel to the debate about original guilt, and this is the debate about imputation of righteousness. "To impute" is a King James term for the Greek logizomai which can mean "to charge to one's account" (the word at Romans 5:13 is ellogeo, a cognate that means just exactly and only "to charge to one's account", whereas logizomai is a broader term and can also mean "to reckon," "to add up," "to consider," "to think," etc.). The doctrine of imputation of righteousness says that we are credited ("to credit" is a good translation of logizomai when used with a positive connotaton in some contexts) with Christ's righteousness; that is, in judging us, God considers Christ's righteous life as if it were ours and so acquits ("justifies" - Greek dikaioo) us, rather than condemning us for our sins.
(A brief note on this word: "justified" is often glossed as "declared righteous," and that's not so bad, except that "righteous" is also a technical theological term, and is also originally a legal term in the Greek, and we don't necessarily know what it means. To be righteous is to be on the right side of the law. To be justified means to have a judicial declaration state that you owe no (further) civil or criminal penalty. This can mean one of two things: either you have been found innocent or the penalty has been paid in full and you can now be released. I've used the translation "acquitted," which is footnoted in the HCSB, because it is easy to understand in this context, but I think Paul plays on the broader semantic range of the Greek word: on the one hand, we are acquitted because of Christ's innocence, but on the other hand, we were guilty and Christ paid our penalty for us. I think these are two different metaphors that Paul intentionally merges in his overally view of "justification.")
While Paul speaks of God "imputing" (or, rather, not imputing) sin in several places, the only talk of "imputing" righteousness in the New Testament centers around Genesis 15:6, which uses that wording in the Septuagint. The longest such discussion is Romans 4, immediately before our passage. This verse, as quoted by Paul at Romans 4:3, reads "But Abraham trusted God, and it was counted toward his [being] on the right side of the law" (my translation - traditionally, "Abraham believed God and it was credited to him for righteousness"). At 4:24-25, Paul connects this back to us and to Christ: "[Our trust] is about to be counted in our [favor], since we place our trust in the one who raised the Lord Jesus from the dead. [Jesus] was betrayed on account of our violations [of God's law] and raised on account of the full payment of our penalty [or 'on account of our acquittal']." (With the traditional theological vocabulary: "[Our faith] is about to be imputed to us [as righteousness], since we have faith in the one who raised the Lord Jesus from the dead. [Jesus] was betrayed on account of our transgressions and raised on account of our justification.")
This, as I said, leads directly into Romans 5, the first verse of which says, "Therefore, since our penalty has been declared 'paid in full' because we have trusted him [lit. 'from trust' or 'because of trust'], we have peace with God through our Lord Jesus Christ." (Side note: I'm beginning to understand why translators use the traditional theological vocabulary - translating into plain English is hard work, and I'm not sure I'm even succeeding!) The traditional Protestant view can be seen as a pretty straightforward inference from this passage: because we trust in Christ's rigtheousness rather than our own, God judges us on the basis of Christ's righteousness, rather than on the basis of our own. There is a lot of Biblical support for this kind of idea, especially in the prophetic books, often with the metaphor of clothing (e.g. Isaiah 61:10, 64:6, Zechariah 3) - I have no intention of tracking down every passage to this effect, because there are a lot of them. In fact, I think this is strongly enough supported that the parallel to imputation of righteousness can be used as an argument in favor of original guilt! Nevertheless, it remains an inference from the text, rather than the immediate teaching of the text. The immediate teaching of the text is something more vague and general, as original sin is more vague and general than original guilt. The text teaches that Adam's sin brought sin and death into the world for everyone, and Christ's righteousness brings life, peace, and justification into the world for everyone who believes.
As this is an inference, there is room for a view parallel to the original-sin-without-original-guilt view: the Christ's-righteousness-without-imputation view which, if I understand this article correctly, may be the view of the Eastern Orthodox Church. The author says "For a Christian, the beginning of eternal-life is the beginning of his belief in Jesus Christ. For him a promise has been given, a reward for eternity because, 'Who soever liveth and believeth in Me, shall never die' (John 11:26)." Later he also says, "Repentance is the exercise of the free will of man, without which there is no salvation ... Repentance is ... the human reaction to the appeal of Jesus Christ." Christ, his righteous life and sacrificial death, his promise, and our trust in him are thus all seen as essential ingredients in salvation. Later, however, judgment is said to be according to "faith and deeds on earth" and reference is made to "the moral progress of the soul." Now, this is admittedly a little vague, and I'm going to interpret it charitably, keeping in mind that the Orthodox theologians who say these things intend them to be compatible with Scripture, including Romans. What could this possibly mean that would be compatible? Well, first we note that repentance and faith are seen as the beginning of this process - no good deed or "moral progress" occurring before this can please God in such a way as to acheive salvation - and that repentance is seen as a "reaction to the appeal of Jesus Christ." We further note that Pelagianism - the view that man is capable of initiating and/or accomplishing his own salvation - is regarded as a heresy in the East just as in the West. The story of salvation begins with "the appeal of Jesus Christ." Only after Christ makes his appeal to us can there be good deeds and "moral progress." We can then understand this Christ's-righteousness-without-imputation view by comparison with the original-sin-without-original-guilt view. Remember that because of Romans 5 we ought to say that we have Christ's righteousness in the same way we once had Adam's sin. As a result of Adam's sin, "death spread to all men because all sinned." We now claim that because of Christ's righteousness life can spread to all who believe, because all can live righteous lives. After repentance and the new birth, the believer can say "I have been crucified with Christ; and I no longer live, but Christ lives in me." (Galatians 2:19-20) Christ in the believer now does what the believer could not do for himself - lives the life pleasing to God. On account of this life, the believer is judged to be righteous and acquitted of his sin. (Everyone who has begun the process - who has repented and believed - counts as "saved" in the Evangelical sense of that term. The Orthodox writer combines the "Great White Throne" judgment by which one enters heaven [Revelation 20:11-15] with the bema judgment for the heavenly reward [2 Corinthians 5:10].)
Now, what this theory needs, which is not mentioned in the article I linked, is an account of atonement. I don't necessarily mean penal substitution - I regard the doctrine of the atonement as an essential point of orthdoxy, but penal substitution as a probably correct but certainly incomplete account of the atonement. If this theory is to work, we cannot claim simply that the believer is "a new creation ... the new things have come;" we must also claim that "old things have passed away" (2 Corinthians 5:17), and the clear Biblical teaching is that, one way or another, it is the death of Christ that takes away our old sins (Romans 6:1-11, Ephesians 2:14-16, etc.).
By way of conclusion, let me say that I regard the traditional Protestant view as solidly Biblically and historically orthodox, whereas the view that I've been sketching here I say might be made to be both plausible and orthodox if sufficiently strong pictures of depravity and atonement can be annexed to it. This is far from an endorsement of this theory, but I present it for your consideration in the hope that it will cause you to reexamine your assumptions and think through the Biblical and rational grounds of your beliefs. Good luck!