I always have plenty of food in the house, so could manage for some time, even if we had to eat strange combinations.
I have bottled water and lots of soft drinks, so we'd be ok there too - I think we'd last a week, or even two if we were very disciplined about it.
I have a camping stove and gas, but it would have to be used outside, so not ideal in a serious storm. I have an emergency box, which is just a means of keeping things together- on the whole I could just go and get blankets out of the linen cupboard etc, but I don't want to be running around looking for things in an emergency (or in the dark).
The box contains, from memory: several battery operated lanterns, 100 AA batteries and 100 AAA ones, thermal hat, gloves and neck warmer sets (one each for husband and me), hand warmer heated things, power packs, a first aid kit and OTC drugs such as paracetamol and Imodium, playing cards, a wind-up radio/torch, a whistle and loo rolls.
I may have forgotten something, and I will be adding to the supplies with each weekly shop. Obviously if we need anything in there outside of an emergency we will use it, but keeping things like that in a box in a spare bedroom means that I know what we have and where it is. Things like batteries in the kitchen drawer get used, so in an emergency there could be none left. Same with loo rolls. My husband is more or less oblivious to it all, as he thinks the advice is scaremongering, but I am always more comfortable being prepared for things.