Nietzsche has his own moral maxim -- "Act always in such a way as to act out of strength, rather than out of weakness." For a peculiar gloss he provides on that, check out the quote in my signature from one of his letters.
My own personal belief is that morality stems from our nature -- we are created so that our end is union with God. I think it's contingent what the exact commands are, and we don't understand our nature or God's nature well enough to know what commands are contingent and which are going to be the same in every possible world. We learn about morality primarily through God's words: Christ, the Bible, and the natural world.
Now, that depends on a number of assumptions that most of you probably don't share. But there you have it