My iPad 1 and 2 both have generic TPU back-only cases, which I like best. I don't like flaps and such.
I also usually have both iPads rigged with wire photo stands that I bent, so that they firmly grasp the iPads. The stands serve as stands and handles, and they can hang onto a steering wheel if I'm in a car, or serve as a handle as I walk upstairs or down.
I have two Jambox Bluetooth speakers, which I use for audiobooks, music, podcasts and movies. I like having two, so I'm never without one that's fully charged. Love them -- good sound, portable, easy to pair, good interface, with about 10 hours' battery life.
I also often use my Camera Connection Kit. My stylus and Apple Wirelss Keyboard, not so much.