I'm mostly using a MacAlly Bookstand case:
http://www.amazon.com/Macally-BOOKST...5256541&sr=8-1
I use it both in upright landscape mode and in typing position. It's not a very protective case, but it functions well for display and use.
DH and I also use these Peeramid bookrest pillows heavily:
http://www.amazon.com/Hog-Wild-Peera...ref=pd_sim_k_1
I originally bought them to support my Kindle, but they work even better with the iPads. I find myself using it in bed to play games like Solitaire or Angry Birds, for reading, and for casual surfing.