I have the Victorinox Paring knife (very sharp) and a draw knife for the fur shed. They are a good price.
For the field, I have a Swing blade, and a Knives of Alaska muskrat knife. they usually only need sharpening once a year. (I have used the muskrat to skin 30+ coyotes, and 2 elk, and 1 deer on a single sharpening)
For a knife in the field, you want something that is sharp.. But i do caution that when pulling/pushing the hide off, you don't want something that is too sharp. Sometimes you are a little tired, or doing this in the dark, and with a really sharp pointed knives, you can nick the hide, which will cause you more work later.