This humidifier is small and subtle enough to work in any room, but I've settled on using it in my bedroom. It's very quiet and doesn't take up much space.
It has 3 options (low, med, high) with an indicator which setting it's on but the best part is the indicator turns off! That means I can maintain the darkness in my room at night because my humidifier light isn't shining toward me from my night stand. 
As it goes through water in the tank, there is an occasional glug-glug sound, but it's so quiet, you'll forget it was even there beside the fact you wake up feeling great (no dried out sinuses)! 
I would definitely recommend this humidifier if you are looking for something on the smaller side.