Wild Country Compass with built in mirror.
The best piece of equipment (apart from a Knife that is) in your kit.
So get one, learn how to use it, and keep it in your belt kit or day pack.
This one is cheap, it works as well as a $200 one, and could save your life.
GPS is fine, but what if your batteries are flat ?
A compass does not use them and is an essential piece of kit.
Follow the example of an SAS trooper, he always has a compass so you should too !