Got back from Walmart. Just wanted to chip in what I seen:
PS3 was sold out completely.
X360 was mostly sold out, there were like 5 left on the shelves.
Wii U was sold out completely.
PSVita looked like it didn't sell one at all.
3DS had quite a few on the shelf.
Wii had a lot on the shelf.
This is by no means what's happening everywhere of course. Just in my area.