Flashlights do a poor job when you need to light up an entire room, or if you need your hands free for a task. Diffused light is what you want, and the Coleman Divide + Push Lantern does a very good job. It’s smaller than the typical Coleman lantern, which is good as it will likely spend most of its life in storage. There are two settings: 425 lumens at the top for 40 hours of battery life and 50 lumens at the bottom for 330 hours of battery life. It uses three D cells which sounds like a lot, but alongside other full size battery operated lanterns like the Coleman Twin LED Lantern which uses eight D cells, it is economical.
You can leave the batteries in it, even if you are using alkaline. When you are not using the Divide +, rotate the battery compartment to separate the batteries from the contact terminals so that they do not corrode during (smart!) Storage. There is also a retractable metal handle so you can hang it on a carabiner or hook.
A water purifier
Most of the time, your water supply will work even if there is a power failure. But major natural disasters can knock it out or damage it, and you might just get dirty water. The Grayl Ultralight compact scrubber bottle is a strong, fast single-person filter that will last 300 uses – a total of 40 gallons – before you need to change the filter. This is what I trust when I travel to countries without guaranteed sanitation.
Another option is the Katadyn Steripen Adventurer ($ 100), which purifies using ultraviolet light. Immerse it in your water and stir. It doesn’t filter sediment, but it’s small, lightweight, and runs on replaceable CR123 batteries. You can also try Katadyn Micropur Tablets ($ 14). They are inexpensive and easy to store. Drop them into the water and wait briefly. The taste is not great, but in my experience no water treatment tablets or droplets are. Another option is LifeStraw Personal Water Filter ($ 30)– Just drink it like any regular straw and it will filter out 99.99% of waterborne bacteria for up to 1000 gallons of water. If you have a big household, you might prefer something like the MSR AutoFlow XL Gravity Filter ($ 100). Gravity filters take longer to purify the water.
You can boil water, but it will not filter the sediment, and boiling uses fuel and takes time.
A propane camp stove