Hardspell has posted a several screenshots of what has to be one of the first DX10 demos and this one comes from ATI. It shows the Earth in not quite all its glory, but rather quite reflected and spread out over a ceiling in a room. The demo is called Light of the Earth and only works under Windows Vista, as it's DX10 only.
Looking at the screen shots, it seems like the card used only manages to produce around 45fps, so it seems like it's quite an intensive demo, even though the screen shots doesn't look that impressive apart from the light and shadows. The light source can be moved around the room and there are some other object that are being illuminated as well.
We have included a couple of screen shots for your viewing pleasure below, but you can check out the whole story in Chinese here and there's even a little video snippet that you can take a look at on the last page.