I tend to have a shotgun and rifle on the wall, covered out the way and a revolver in the draw and a knife, extra rounds and so on, so I pretty much have anything I need fairly close by. It also lets me have a second or two to come to my senses and not be on automatic control.
I wouldn't dream of putting a pistol under the pillow. There are just too many incidents of people knocking it off the bed or it being set off by accident, especially since I have a dog in the room as well as my wife. Thats just causing for an accident to happen.
My mother in law has a compartment built into her headboard that stores a .38 snub within grabbing distance.