I agree with @LuckyGuy you probably have quite a bit around the house already. I never buy a ton of stuff before a storm. Buying a lot of snack food, means I wind up eating a bunch of junk. Buy, a few packaged items, but don’t go crazy. Also, make sure to buy or bottle some water.
I know you didn’t ask, but here is a quick list of things to do:
Fill your cars with gas.
Have some extra cash on hand.
Plug up your bath tub full of water (this is so you can flush your toilet if there is any troubles with the water system).
Have a couple weeks or more of meds on hand if you take anything daily.
Make a lot of ice. If you have igloos or styrofoam containers, food will keep colder longer in tightly packed containers of ice, than in a fridge or freezer. I am not recommending to take food out of your fridge as soon as electricity goes out, but once 6–8 hours have gone buy it is usually time to start moving it out of the fridge and freezer to keep it cold. Move the ice right away though, into one container packed tight so it doesn’t melt, once you move food then you can divide up the bags of ice into two or three containers with food.