Based entirely on personal observation, it seems that Boston's In Cold Blood-mania - propped up for the last couple of years by near-constant releases of one film or another about Truman Capote - has begun to abate. Through the late summer, it was near-impossible to find a used copy of the book in any of the Boston shops (I know, as I was hunting one up for a customer). Yesterday, however, I realized that we had two copies in stock (at once!), and both had been in the store longer than a day.
Maybe it's just because the title doesn't make the book a particularly appetizing holiday present, but I think that perhaps the fever has broken.