In the most recent edition of The New Republic, Nobel Prize winning economist and philosopher Amartya Sen argues for upholding the importance of the UN Declaration of Human Rights sixty years after its signing.
Sen argues that:
1) the UNDHR makes an important contribution to ethics by establishing the priority of morality to law. Human rights do not depend on governments to establish laws to enshrine them–they apply to human beings as such regardless of their nationality.
2) the UNDHR empowers many different kinds of organizations, not just governments and law, to protect human rights, such as international non-governmental organizations (Amnesty International, etc)
3) the UNDHR goes beyond many of the great documents protecting rights (such as the American Bill of Rights or the French Rights of Man and Citizen) by making explicit mention of social, economic and cultural rights, and tying issues of wealth and poverty to political and civil liberties.
4) the UNDHR, again unlike other rights documents, is explicitly universal in scope, with the hope of including within the sphere of moral concern many different groups that have been marginalized throughout history.
You can read his powerful defense of the UNDHR here.