There are several things people just have to have in life that we can live without but don't want to. Coffee, tea, sugar, alcohol, cigarettes, colas, beer, & chocolate. I plan on stocking up on them and keep them in case I have to do some trading. I don't drink or smoke but I don't have a problem buying it for bartering or trading.
I will also stock up on aspirin, ibuprofen, bandages, and all first aid items. Bug spray & sunscreen are all important. Best to keep year round too.