WARNING: THAR BE SPOILERS!
One thing I find strangely missing from all these posts describing "'V' for Vendetta" the book or the movie is the intimate connection between them and two books: Dumas's "The Count of Monte Cristo" and Bester's "The Stars My Destination."
The movie, and I assume the book, allude in at least two scenes to the classic story of betrayal and revenge. V is a man scuplted by injustice, that injustice is what drives him to exact revenge upon the ones responsible. His name is a constant reminder of his anger, his purpose the only thing for which he strives. V is part of a triumvirate of revenge seekers along with Gulliver Foyle and Edmond Dantes, each is nuanced and a separate character with a common motivation. V is more similar in character to Foyle, both have no past and are willing to commit any evil destroy those who wronged them. But all three end their quests in different ways, suggesting that all three have starkly differing characters behind their quest for revenge. V dies at the end of his quest, having killed those who made him what he was, he destroys Parliament along with himself. Foyle attains a sort of godhood, rejecting his humanity to be reborn once more in the cabinet that had acted as his prison. Dantes regains his humanity after having punished those who destroyed it.
Moore's work is a brother to the works of Bester and Dumas, easily standing shoulder to shoulder with them. They all investigate a basic dark core within the idea of human justice. It is the voice within all codes of law that says "I'm gonna make those bastards PAY!"