I was asking about this at the top of the page, but I think it might have gotten buried since the thread moves so fast.
NG is 1 million, that's what I have heard. NG+ is 2 million, but 2 million during that playthrough (so souls acquired in NG don't count towards the NG+ soul requirements)
I am carrying around 1,200,000+ souls now, because I read that you need that many souls on hand somewhere, but I believe that is misinformation. I am 6million+ in souls memory, but the door isn't opening for me in NG+ just yet, so I probably haven't hit the 2 million in this playthrough. It's hard to tell how many I have gotten this time around since you can't tell how many you earned before you started a new game :/