I ordered a clear back cover for mine and just received it today. Now I see that it just looks silly. There's nothing particularly wrong with the simple case/cover -- it just feels a shame the idea of leaving it on all the time
so I probably won't.
The reason I got it though is because I too feel a little irksome about placing the iPad directly down on a hard surface. Other than this new case though, I just use a smart cover and a simply suede sleeve from sfbags to sometimes carry it in. It might be nice to have this back cover around in case I need it, but I don't think that it's going to live on my iPad for extended periods of time.