Wow, I didn't expect to see a thread like this on HBT, especially not in the drunken ramblings category.
But as a current philosophy major, I thought I would put in my opinion. I have not read Rousseau, but I have read some Nietzsche. I voted Nietzsche, mainly because he's the one of the two that I am familiar with, and because there is a lot of his ideas that I really like. And as to the question at hand, generally I will agree with what TheJadedDog said but add this 'however'.
The reason that I disagree with Locke, dislike Kant, and despise Mill, is because I think that they all offer too easy of an answer to a hard issue that we all have to deal with as humans living in a society. I think that this is one of the issues that humans have been dealing with since the beginning of organized human society, and I don't think that the answer is to be found in a Utilitarian "do the most good for the most people" maxim, in Kant's categorical imperative, or underneath Rawl's veil of ignorance.
With that being said, I don't endorse the simple statement that morality was invented by the weak to control the strong. However, we have to look seriously at the nature of ourselves and of society. If society is a construct that we created for the mutual benefit of all members, that we assume any one of us would have voluntarily joined into given the chance, then how can we justify any injustice against the individual for the sake of the group. If we agree that humanity is something that is intrinsically valuable and ought to be preserved at any cost, then how do we avoid offering help to any person who needs it. If we realize that there are individuals who bring more to the collective than others, how do we treat that person better without compromising our idea of intrinsic human worth. How do we make a society that is designed to provide minimal cost to each person while providing each with a maximum return, without compromising whatever idea of worth we ascribe to humanity?
I don't have the answer to these questions but I have the idea that humanity does have some sort of intrinsic value, but this value exists due to the qualities that make humans different from other animals. So i think it follows that since humans hold these qualites to varying degrees, some are more valuable to society than others. But at the same time I think that each person, regardless of his or her degree of value to society, has a life that has meaning to themself, and we have to remember this when we are designing our social institutions.
So we have to balance our mutually beneficial social order, with a strong sense of human worth. And I don't think that Mill, Kant, or even Nietzsche, fully understand the significance, and complexity of this question (Rawls does to a higher extent than those three). But the answer isn't just that f-ing simple.
okay, went a little long winded there, but yeah, RDWHAHB
