Streak III'm leaning toward the green for New Orleans, simply because the fit is a little better than the pink (women's 12), but all things being equal I think I'd rock the pink considering it's the Mardi Gras Marathon.
So anyway, this post is nothing more than a shameless plug for Pearl Izumi's new Streak II, which is either already available or will be within the next week or so. I've had the good fortune to run in these for a few months now, and can safely say they're the best road flats I've ever worn, which is not necessarily saying a great deal as I've only ever owned two different pairs (beyond the Streak), but still...
Anyway, they weigh in at about 7.7 oz in the 9.5, which while not in the uber-light category is still a distinctly light feeling shoe. Wear testing suggests they're good for at least 300 miles, which is a large number for a road flat. The extra ounce or two in the Streak II versus the hardly-there flats (4 to 6 ounces) comes in the form of a little extra cushioning in the midsole and a little added structure to the upper. For me, this makes the Streak an ideal shoe to race the marathon distance in. The legs are always the first thing to break down in a marathon, so hopefully the extra cushion will allow the legs to hold up a little better to the relentless pounding of 26.2 miles on asphalt.
With all that said, no shoe in the world is going to prevent a full-on bonk if I go out too hard, so I sure hope I've guessed my pacing right.