Paper goods. In an emergency there might not be water for washing, so a supply of paper plates and cups as well as plastic silver ware will cme in handy. You will also need a sufficient supply of toilet paper, since that always goes first in emergencies!
Medications, medical supplies, personal care things like soaps, toothpaste, etc.
Vitamins. Sunscreen. Lotion, vaseline.
Plenty of socks and underwear. Good shoes. Warm clothes. Blankets.
This isn't a need, per se, but I was thinking books to read, maybe puzzles to do, things to keep a person occupied.
SALT. Salt has a multitude of uses, is essential to the human body, and right now it's cheap. I pick up a box (28oz) every couple weeks when we make a trip to the store (0.45). I have iodized and non-iodized. Iodine is also an essential element. Along with all it's benefits, it would also make a great barter item in the event that it was in short supply. I also keep a few 50lb bags of rock salt around. You can't make ice cream without rock salt.
Don't forget a high quality water filter capable of removing pathogens and particulates down to 1 micron or less.
While chemical sterilization with ordinary Chlorox is fine, a good water filter such as an MSR Mini-Works is great insurance against water-borne diseases. Mini Works Water Filter
Don't forget some soap to maintain good personal hygiene with that clean water after you've adequately hydrated yourself.
Most casualties requiring personnel to be evac-ed from combat areas are caused by vector borne and water-borne diseases, micro-evils and simple vile crud which you can avoid with proper attention to avoiding exposure to disease organisms, staying well hydrated, avoiding tainted food or drink and keeping wounds clean.
Without your health all that other stuff you have will just leave a well equipped corpse for the people who find you to divide up your gear!
If you have small children, candy and gifts for holidays. Chocolate for the ladies in your life (my wife and daughters say chocolate is a vitamin). If you grow a garden and do not save seed, learn how and start.
Water distillation unit is a most. Some water are is so heavy with minerals that filter lose their effectiveness. Distilling helps remove the the minerals and toxic chemicals that filters will not remove.
Agree distillation is the most effective method. Unfortunately, I know of no of-the-shelf models for home use under $1600. This article describes how to build your own, or if you live in West Virginia ask your local moonshiner...