Dan McLaughlin at Red State furthers an argument he made a while back that the filibuster is important to US law because it prevents temporary majorities from enacting permanent or overly complex legislation that may radically alter the American system of law and be probelmatic to reverse. In short, the purpose of the filibuster is to allow a minority to slow down legislation pushed by the majority. For those on the Left who think this is a travesty, I think it serves as a vital reminder that our country is not, and was never intended to be, a democracy.
The Senate is designed to ensure that no great and complex changes can come to the law, but by operation of the great majority of the people in the several states. The Framers designed it that way. We should be rightly suspicious of those who always want to change the rules when they cannot get their way.
McLaughlin makes his case by going back to the Source, and allows the words of James Madison in Federalist No. 62 to speak for themselves on the matter.