One important question for my own life is how I want to approach ethics - what's the right thing to do in a given circumstance? I'll take a look at several competing theories, and determine which one best fits me.

• Egoism: Egoism states that one should do what benefits them the most, rather than being held to an external moral code. Obviously, this is an appealing philosophy to choose, since it essentially excuses you from any responsibility; but I find it distasteful. If we were all egoists, society would be a living nightmare, and so I don't think this philosophy is acceptable. Of course, that reasoning is linked to the universal maxim, which I also don't really accept; so maybe I only oppose egoism because it makes me uncomfortable, and therefore does not benefit me. Which means that not accepting egoism is the egoist thing to do. Huh.
• Consequentialism: Consequeuntialism is the idea that what matters in ethics is the result. In particular, utilitarianism (also discussed on the Politics page) posits that one should take the action that brings the greatest good to the greatest number of people (or maximizes the sum of the population's utility function). This sounds great in theory, but runs into a couple problems. First, you need to define a utility function; do you assign everyone the same function? If so, who gets the privelege of determining what the "greatest good" is? Or do you take into account each person's preferences? If so, what happens if you have someone that enjoys murder so much that the utility they gain is greater than the utility lost by their victims? And what of examples like the doctor killing a healthy man to harvest organs to save 5 lives?
• Deontology: Deontology states that one is bound by duty to follow certain rules. Some of these theories appeal to religious authority (which I don't accept, as detailed here), but the most well-known variant is that of Kant. He declares that, in any given situation, you ought to do what you would accept as a universal maxim. Is it okay to break a promise in a pinch? Well, if everyone did that (the universal maxim), promises would be useless. So, no, it's not acceptable. Like utilitarianism, however, this runs into certain adversarial examples. If a murderer is asking you where your family is - and you know - most people would feel it's acceptable to lie in order to save lives. But according to the universal maxim theory, you should let your family get killed.
• Virtue Ethics: Virtue ethics, as championed by Aristotle, argues that one should act in order to attain certain virtues, such as courage and wisdom. One problem is that the list of virtues is inherently arbitrary, and strongly dependant on culture and personality, in contrast to the other theories. Another problem is that actually applying these virtues is difficult. Would charging into a bar fight, in which your friend is threatened, by acceptable? In one viewpoint, yes, as that is courageous and supportive of justice (assuming he didn't instigate the fight). But by another perspective, no, as that is unwise and violent. If you extole both courage and wisdom as virtues, or both justice and peace, what do you do?
• Machiavelli's Approach: Machiavelli had a rather nontraditional approach to ethics; the most important factor in what you ought to do is what you need to do. If a state needs to use violence to ensure stability and prevent a coup d'etat, then that is what they should do. Machiavelli was primarily concerned with stately princes, so the "need" is taken to be "maintaining the state," but these ideas could be translated to other realms. However, Machiavelli does believe that, when acting immorally is not necessary, it should be kept to a minimum, and princes should act virtuously. So, in a sense, the Machiavellian approach combines egoism and virtue ethics... and I think it has the faults of both.

Unlike many of the other pages, I don't think I can come to a concrete answer. None of these ethical codes are satisfying. Egoism is repulsive, utilitarianism and deontology have adversarial examples, and virtue ethics is vague and contradictory. Perhaps the best approach is to consult the original position, as detailed here. While Rawl's argument from original position is usually viewed in terms of politics rather than individual ethics, it can be a helpful way to think about moral issues. I believe it resolves both adversarial examples from utilitarianism and deontology; however, it can also be pretty vague at times. In the end, I'll probably just do what I feel is right, since philosophers have yet to come up with a ethical theory that satisfies me.