The thunderhead over the US midwest is spectacular, and humbling, and for some reason it bothers me. Maybe it's similarity to a mushroom cloud? Maybe.
The picture of a cloud over China made me think of how lonely it must be to silently circle the Earth, looking straight down over landscape you can see but cannot touch, and maybe, at the time you look, not even know the location.
But my favorite is the last one. I spent some time last year looking for a really good shot of the Moon near the Earth's limb from space to demonstrate the distortion caused by our air, but this one is phenomenal. Best I've ever seen!