Stu - On a practical note, I seem to do much better with carbs PRE workout as well. I workout mostly in the evenings during the week, so it's 8pm or so by the time I get back home for my last meal. I'm definitely not 'carb friendly' so a ton of carbs at that time, then bed would not be the best.
I've done the POST w/o carbs before bed thinking that the training would take care of the carbs and don't think it was wise for me in terms of composition (lifts still go up though). That's not to say others wouldn't do well.
On the weekends I workout earlier in the day like late AM or early afternoon. That leaves a lot of room for carbs POST w/o if I chose.
I do like having the 'fuel' ahead of time though.