I have a full house humidifyer. What humidity level do you think is correct in a dry climate during winter?

Peter is correct, technically. However, you may want it lower. What is the humidity level outside? If you're in and out a lot, keeping the humidity higher in the house is really a pain, and can be a waste of energy. Don't go above 54 percent no matter what, but you could go as low as 30 percent, if it's low outside. Moist air will feel cooler, or warmer, even though it's the same temp as dry air, so sometimes having the humidity up saves on heating and cooling bills. However, it does take energy to put that humidity in the air. You might do it like with heat and or air conditioning, not so much when you're not home, but raise it (automatically would be nice) in the evening and other times you're home.

I go by my nose. If I wake up with nasal crust, I am sleeping in an area that is too arid.

I usually set mine at 50%.