The Hateful and the Obscene, by University of Toronto philosophy professor Wayne Sumner has been suggested by a reader as a thoughtful addition to the current Free-Speech debate.
Synopsis: Before he began to investigate the matter for his book, Sumner thought that he would be arguing in favour of provisions such as 13 (1) of the Canadian Human Rights Act. As it came to pass, though, he discovered that none of the few empirical studies of the effects of hate propaganda laws supports the thesis that such laws either protect people or ameliorate their condition. He concludes that laws against hate are unjustied government intrusions on civil society.
An excellent on-line preview is available here.
A review is available here, in which the author seems less an absolutist than I had hoped;)