I went through Hurricane Hugo in St. Croix Virgin Islands. The island was wiped out including my place and all I had.
I lived without electricity for 8 months and I understand what you need to have to survive any duration without. But I was not in the densest city in the United States, which I can imagine being stuck in without utilities. My story is not what is important, but understanding I have survived and endured not having electricity or capabilities for months and I know what I am talking about, is what matters.
There are very important items you absolutely have to have for even the shortest amount of time without electricity.
I am asking all of those who are in the line of Hurricane Irene, especially in NYC to please stock up on these items immediately and take these steps immediately. It would be better for you to get out of the way and evacuate.