I've always found that the same knife I use for gutting - something like a Buck 104, or say a Ka-Bar "Lil Finn" - keep it sharp, and use the "sweep" of the blade. Working with 2 people (one to hold the deer still from swinging on the spreader), I can usually skin a deer in 15-20 minutes with one, and another 10 minutes to have it sectioned, in bags, and ready to go home for final butchering