I would hazard a guess that the majority of KSP players use the default mouse-and-keyboard control settings to fly their ships. For those of you who don't, I'm curious to hear about what you use.
I, for example, have an old Saitek Cyborg joystick that I picked up from a garage sale. I've found that having that in my left hand and using my right hand to control the mouse works pretty well, although I'm not as good of a pilot with the stick as I am with a keyboard (yet).
What about you guys?