For my two iPad1's I use the black Apple cases. They are thin, and protective, but still can slide into my STM murce. No screen protector, what for, these things are incredibly scratch resistant. I am really careless and haven 't done a thing to any of them. The iPad 2 my wife usually uses, with the Apple magnetic cover... It is fun to watch, usually she is fumbling with two pieces, by she has very bad arthritis... That could be it.
I use one for research, and got a Moleskine cover. It is wonderful. Tablet of paper for taking notes on right and iPad on left. Perfect to make it into a research tool! JD