Nyarlathotep said:
Good points in your post, but I can see where "good" actions that you are willing to sacrifice all for can easily end in an "evil" result. If you never compromise your principles and beliefs and others die because of it, isn't that evil even if your intentions were good?
In a world in which principles and beliefs have tangible meaning, perhaps not. Moral issues do not always have straightforwardly utilitarian solutions, and often, the surest way to corrupt morality is to offer such a solution. An example might be as follows: Suppose that you *know* the only way to prevent the deaths of one million innocent people is to kill one innocent. Now say it's 100 innocents (precision bombing, say). Now say it's 1000 people (carpet bombing). Now say it's one million minus one (nuclear preemptive). Which is the morally correct solution?
Okay, super-contrived example, but it's late.

I don't doubt that there are situations in which a compromise of principles and beliefs is
truly necessary, but that's a matter of wisdom, not alignment. This, of course, is where morality gets complicated. I don't know that any of us in the real world have figured out the answers to some of those questions, and that, IMHO, is the point. Alignment is there in
order to complicate things. Heroic sagas that make it easy to know and do the right thing would be kinda boring, wouldn't they? Even stories in which the heroes are supposedly morality-resistant (pulp and noir stuff ranging from
Conan to
The Shootist to
Chinatown) find those heroes doing the right thing even when it's not so convenient or predictable for them to do so.
My point is that alignment simply offers a way to make tangible some of the heroic elements without which it's all too easy to engage in MMORPG-style killing things and taking their stuff. Alignment, and especially being good, offers serious role-playing dilemmas and character conflict, which, handled well, can make for excellent RPing. It shouldn't be taken as a "crutch" for DMs or a raison d'etre for players, but an aspirational element. Putting down "Lawful Good" on your character sheet should be a statement that you to WANT to uphold the highest ideals of Law, Justice, Mercy, and Benevolence, and that an essential part of your PC's life mission will be to do those things... unless he changes his mind.
I've come to the conclusion that alignment is one of the sacred cows of D&D that should be turned into hamburger and then into a fine chili, eaten and forgotten about. Too often it has no effect or is used to screw players (I'd hate to play a paladiin under most circumstances). There are some campaigns where that is not the case, but I believe they are few and far between.
To a certain extent, I do agree, but not entirely. I've dispensed with alignment in favor of a virtue and corruption token system (I play Iron Heroes), but I do miss certain elements that alignment adds to the game. I've had great games featuring alignment issues aplenty.