I have about 10 hunting knives that I use regularly or semi-regularly (I keep several with me when I'm skinning/gutting/quartering a deer), but I think the best design (and the least fatiguing to use) is the D. H. Russell (Grohmann) Trout and Bird knife. I love the design (and the design of the "Original Canadian" from the same maker). However, the steel doesn't hold an edge quite as well as more modern steels, such as 154CM or D2.
I have a Ken Onion skinning knife with a D2 blade, and I really love the steel on it. It's good for 2 deer, start-to-finish, without resharpening!
Another one I like a lot is a Buck model 142 C folder, with an ATS 34 stainless blade. It dates from before Buck moved production to Red China, and is, in my opinion, the best design Buck ever released, and one of the best folders ever made by anyone. Sadly, it is now discontinued. The steel is excellent and holds an edge quite well. It's easy to open with one hand, and its slim profile awards it a ride in my pocket any time I'm hunting or hiking.
Probably my favorite all-time hunting knife is one which wasn't designed for hunting....an Al Mar Quicksilver III design.
It isn't what most people would think of as a hunting knfe, but I absolutely loved it. The steel was ATS34, and I could get it sharper-than-razor sharp; it would go through a deer as if through warm butter. Unfortunately, when I moved back to KY from MD, it disappeared during the move. More unfortunately, it is a discontinued design. I wish I could get another, but they were low-production to begin with, and used ones cost $$$$.