In the summer I pack an Eos, it is compact with good output and long battery life but I find it difficult sometimes to turn it on/off when wearing heavy gloves or mitts.

In the winter I usually pack a Myo 3 because it uses AA Lithium batteries and has great output which can be handy for navigation with the long winter nights. It is bigger than the Eos so I don't usually pack it in the summer but it is always in the car.

Also note that some lamps will not work with lithium or rechargeable batteries so check with the manufacturer if that is a requirement for you.