My fav is the chin-up. Like super_rice said you should do them all (and add weight).
I disagree that a kipping pull-up in not a pull-up. I think kipping pull-ups (and strict pull-ups) have their place in a training program. For example if you are trying to increase you max rep pull-ups number, you can do 15 strict and then do 2 or 3 with a kip. Or if you are trying to get your heart rate up and fry your back at the same time, you could do 30 kipping pull-ups supersetted with shoulder presses or whatever. My point is there is a time and place for kipping pull-ups as well as strict pull-ups.