Nurumaiel, I agree with your stance that pride is not necessarily sinful in all manifestations. Narcissistic pride and extreme condescension are generally considered 'sinful' by religious types ('annoying' or 'maddening' by non-religious types), but certainly most of us agree that there is nothing wrong with moderate pride in one's accomplishments, and a generally high self-esteem (as one does not consider one's self vastly 'superior' to others).
Now, on to the meat of the topic. (Hopefully I won't just be re-heating cold gristle.)
Gandalf is representative of each of the seven heavenly virtues. Morgoth is representative of the deadly sins (though I don't know about sloth; does hiding in an underground chapter count?). The first is the leader of the 'good fight' in
The Lord of the Rings; the latter, the ultimate root of evil in Arda. The fact that each of the virtues and sins is so clearly displayed in (respectively) two characters is, to my mind, not really indicative (per se) of a specifically Catholic (or Christian) influence as it is of the 'Western morality' that is necessarily part of modern literature - especially literature that deals largely in the topic of 'good v. evil'. The sins and virtues are, more or less, the bases for Western moral ideology - arrogant people, murderers, adulterers, greedy CEOs, etc. (
) are looked upon by society as 'bad'; charity/humanitarian workers, trustworthy and 'courageous' individuals (here in America, the firemen, servicemen, etc) are looked up to.
Ok, ok. Most of what I've said isn't really news to any of you - mostly concepts that we take for granted. My point is that the 7 Sins & 7 Virtues are generic enough to be seen in any work of literature. That Tolkien was a devout Catholic does not mean that Middle-earth was consciously imbued with Catholic ideas about sin and virtue to any greater extent than a book written by a Jew, an atheist or a Moslem. 'Good' and 'evil' are simply there in Middle-earth - magnified, yes, and polarized - but no more indicative of a specific knowledge of the Sins & Virtues than of a general modern morality.
Edit: I had to leave the computer for a bit mid-post, and didn't see
Mark 12:30's post. I think you have a great point, Mark. Perhaps with the aforementioned instances of imprudence, Tolkien meant to illustrate the fallibility of 'good' people, while at the same time contrasting the untimely omission of a heavenly virtue with true
sin (sin being an open act or thought displaying contempt for what is considered virtuous).