What's the best way to make a decent looking fingernail shader? By decent-looking, I mean one that is not too complicated but looks realistic enough to look like a fingernail.
It will depend on if the fingernails are attached to the fingers or modeled as part of the fingers. The color comes from what is under the fingernails, otherwise the nail is a cloudy translucent color. There are also waves in the nail running with the length of the nail. The gloss is nearly the same as the skin.
If the nails are for females it maybe best to have them be polished, if for male you can have them short. If part of the finger and long you would need 3 parts, the crescent at the base the main color and the cloudy translucent tips. That means you will need the nail mesh able to support the different materials. So much depends on how you are making your models.