The following is a short (80 min) but insightful radio debate on sola scriptura, the formal doctrine of Protestantism, between Peter D. Williams (Catholic) and James R. White (Reformed Baptist).
While I strongly disagree with his Roman Catholic theology, Williams did a good job at (albeit briefly) discussing the problems Protestants have when it comes to how one can recognise the canon (White confused the ontology of Scripture [that God inspired Scripture] with the issue of epistemology [how one can arrive at knowing what scripture is, a common mistake Evangelicals make). Further, while White is correct that the number of Protestant denominations is greatly exaggerated by Catholic (and many LDS) apologists, such is really a smoke screen--if there is more than one denomination, that is one too many as there can only be one true Church (cf. Matt 16:18-19; 18:18; 1 Tim 3:15; etc), and this is seen how, in Acts 15, it was the Church and its leadership that explicated the teaching that Gentile converts would not have to be circumcised before entering the New Covenant (full discussion of this and other issues here).
White, to his credit, was correct in bringing up Mariology, especially the Bodily Assumption of Mary as there no evidence whatsoever for this concept in the opening centuries of Christian history, let alone it being held up as a doctrine of the faith, until several centuries after this (fictional) event. For a full-blown study of the origins of this belief, see Stephen Shoemaker’s Ancient Traditions of the Virgin Mary's Dormition and Assumption (Oxford: 2003).
Well, enjoy the debate!