In less than 31 hours (my local time), it is going to be insane. The fact the kiddies are all out for summer vacation won't help either.
Don't make Walmart an option. 16GB only and very limited. Go to the Apple Store. More in stock and more options for accessories. Start packing and planning your strategy. There is a meet-up section here. The earlier, the better. 12am-2am will do. I know someone planning to head to my nearest Apple Store before midnight, so that means less than 12 hours from now. Again, with so many teens out, tomorrow is no longer a school night. Social gathering and lots of loitering beyond any curfew.
I already got an appointment set for BB, but I still want to be part of the hype watching a grand opening of an Apple Store near me as well as getting a bumper without waiting in the reserved or walk-in lines. I just want a free t-shirt and accessory, and I'm out the door fast.