I find that it makes more sense when said month/day/year. It dosen't roll off the toung quite as well when said 1 January, 2011 (reading it as First January, 2011), where as saying January 1, 2011 (January First, 2011) sounds better because it implies that January possesses the day in question and makes the sentence flow better. Unless you phrase it as First of January, 2011, then it makes sense. But that's just a humble Canadian's opinion on the subject.