I buy most of my food locally at Farmer's Markets. I do it for a lot of reasons (most of them heavily influenced by Michael Pollan and the like). I am, however, extremely skeptical of the concept of "food miles." The short story is that I think it is a highly oversimplified idea and that the people who follow it with a sort of religious ferocity simply refuse to recognize the complexity of the issue (include accounting for economies of scale and the efficiency derived therefrom) and the extremely difficult overall empirical calculations that must be considered for any individual piece of food.
Anyway, I am not saying anything that hasn't already been said on blogs in the past year, in large part as part of a discussion to an Economist article reacting to Pollan's Dilemma. But the only reason I am mentioning now is to call attention to a thoughtful editorial in the Times a few weeks back that some of you might have missed.