Paul Gowder makes the case here. I think Paul gives short thrift to practicing criminal law, though. You won't make a ton of money as a prosecutor or defense attorney, but it avoids a lot of the problems he mentions.

  UPDATE: I should add, in response to some of the thoughtful comments, that I gather Paul is deliberately stacking the deck to provide a counterpoint to some misunderstandings about practicing law held by a number of law school applicants. Some applicants imagine that a law degree will open the door to practicing international human rights law before the Supreme Court at a prestigious firm that pays them a $1 million a year salary plus free car service at 5pm when the workday is over. The reality is different, and I gather Paul wants those students to know it. The real lesson comes at the end of the original post: "Make this decision very carefully. Don't just drift into it because you're not sure what else to do with a humanities degree."

  ANOTHER UPDATE: Michael Froomkin comments here.