Spent a few seasons working in a friend's father's butcher shop processing deer. At the time, all we used were the Forschner line of boning/skinning knives from Victorinox. For the price, they're hard to beat. If you don't have one, buy a good "steel" as well. They're integral to maintaining a good edge.
I have a 6" Victorinox boning knife that handles 99% of my butchering chores that don't get handled in the field. I clean it, touch up the edge with the fine diamond, and it's ready to go for the next one. I have several other butchering knives, but that's usually the first and only one I go for.
Same here; Victorinox 6 inch curved boning knife with semi-stiff blade. I use it for everything from skinning to boning and trimming.