Oxford English Dictionary definition of Freedom: "The power or right to act, speak, or think as one wants."
Webster's American Dictionary definition of Freedom: "Unrestricted use".
Thus the dictionary definition would agree with the definition of "Freedom of speech" being absolute. The legal definition may disagree, however, my argument to that would follow:
Article 6, Clause 2 of the Constitution: "This Constitution, and the Laws of the United States which shall be made in pursuance thereof... shall be the supreme law of the land." Which loosely translated means "This Constitution and any laws which support this Constitution shall take precedence over everything else." Consequently, while the "Yelling Fire! in a theatre law," which may have been upheld by the Supreme Court, and which are probably more for the good than bad, and certainly protects more people than it harms, is actually an illegal law under the Constitution as it seeks to restrict your first amendment rights - which is quite contrary to the Constitution.
The wording is explicit. If the wording is not permissive enough for the government and legal system to cope with, then an amendment must be proposed and ratified. There are no amendments to the constitution that say "guarantees the freedom of speech, except where we can convince the Supreme Court to pass a law that restricts that in our favor." The Constitution is quite clear and explicit - "Congress shall make no law" so any law that has passed that serves to restrict your Constitutional rights are illegal in the eyes of the Constitution.
Thus your freedom of speech, in the eyes of the Constitution is absolute. It is only an illegal law, which agreed, made in the best interest of the people, in violation of the Constitution that restricts those First Amendment rights.
So what takes precedence? The Constitution or the law? What happens when they conflict? Well the Constitution covers that... "no law shall be passed" which conflicts with the Constitution. So the question becomes what is more powerful, the Constitution or the Supreme Court? I think that can only be answered by the people.
Why am I, as a non-American and non-resident of the United States, debating in defense of your Constitional rights and you as an American (is that a fair assumption?) are debating against it? That seems a little topsy turvy, no?