Power
Rechargeable batteries, especially lithium-ion cells, tend to last the longest. If you choose a camera that supports rechargeable batteries, check to see if it also includes a charger or AC adapter. Some cameras support rechargeables but ship with alkalines, so the charger costs extra. We like Sony's InfoLithium batteries because they're powerful and provide a readout in minutes of remaining battery life. However, cameras that use them can't take other battery types in a pinch.

A broader variety of supported battery types gives you extra flexibility in emergencies, so the best choices can run proprietary lithium-ion batteries (for longest life), CR-V3 disposables (long life in an emergency), and both rechargeable and alkaline AA- or AAA-size batteries for when your only available supplier is East Podunk General Store.