It strikes me that as a moral guide, the ten commandments is pretty lousy. The first five are for maintaining power for those in authority--not really related to morality at all, or worse, they demand you surrender your will to others and let them decide for you, a negative moral argument--and the last five are, mostly, so vague and obvious as to be meaningless. As if killing, stealing, lying, and sleeping with the neighbor's wife were somehow considered good things until Moses straightened them out on that. The only commandment that makes sense to me is not to covet, which seems like good general advice that could do you well in a number of situations.
But even the obvious ones are pretty useless; a good moral guide is not one which sets only the most basic guidelines, but one that helps you with the hard questions. For example, take the classic question of whether or not it is moral to steal food if it is the only way to save the life of a starving child. "Thou shalt not steal" lets the child die. And if the food is being wasted by a rich, fat hedonist? How is letting the child die more moral than stealing from an immoral, wasteful person, especially if one then admits to one's crime and faces the penalties for it? The ten commandments leaves you high and dry in almost every truly tough moral quandary.
On my own blog a while back, I wrote down what I thought would serve as a better moral guide, if I were forced to limit it to ten:
I would hold that someone armed with this list would do a heck of a lot better in life than someone with the ten commandments.
Forgive others their wrongs and focus more on the wrongs you have committed
Show compassion, sympathy, and kindness at every opportunity
Know that others have different views and try to understand them
Help others when they need and will accept help; be willing to sacrifice for others
Do not be arrogant
Use reason: seek knowledge, question information given to you, and think for yourself; always allow for the possibility that you may be wrong
Reign in your fear, anger, envy, greed, and jealousy; recognize them and do not act on them
Take responsibility for your actions, and do not use the actions of others to excuse yourself
Always try to work for the greater good, but first, do no harm
If you must judge others, judge them by their actions alone
It really peeves me when I see Christians who feel that not only did morality spring from Christianity, but that it can only come from Christianity. They seem incapable of believing that an Atheist can be moral, that morality is born from self-awareness, which leads to understanding that others are like us and want to be treated much as we do, and from enlightened self-interest, the idea that treating others with respect will lead to others treating you the same. It's just as disappointing to realize that so many Christians' "morality" is based on fear of punishment--that they believe everyone would misbehave without fear of god demonstrates that they themselves have no internal moral compass, and act morally only out of fear--hardly a basis for morality, especially the "only" morality.
So, what would you add, remove, or change in the list? What does your sense of reason inform you is a guide to acting in a moral fashion?