I have only a small LED headlight stored in the glove box. Very efficient:
.both hand free
.you can use it anywhere, inside, outside, in the garage to grease your king pins.
.not expensive
but not dedicated to car.
by example like this one:
http://www.uttings.co.uk/p121181-ansmann-future-headlight-1600-0044/#.WCBQpWczW70You can find cheaper.