re: How many of you are prepared if there were a power grid attack on the U.S.

Some people will have backup generators. Once the fuel is used, they might not be able to get additional fuel because gas stations require electricity to pump gas.
People without generators will have refrigerators that will not keep anything cool after 48 hours. That food will have to be eaten and frozen food will have to be cooked. Can cut down trees to build a fire to cook. Will need to hunt/fish.
Will need sleeping bags/blankets for the winter, plus wood to build a fire.
Will need to boil water or have a filtration device, but I'd still boil it if you can.
It will be every man for himself, and after 3 days forget the cops. Getting full will be a problem.
If a person has a generator, the need to make sure their battery is not connected. An electromagnetic pulse will fry ALL electronic devices with power flowing or connected to a battery. This means no batteries in flashlights, etc. After using your generator remember to disconnect the battery terminals. also, use a battery tester to test the battery monthly.