I've been running F17 beta since it was first available - having installed it fresh on my netbook from the live CD. I haven't found many show stopping issues, so a note about the wallpaper will seem very trivial
Ubuntu had wallpaper that changed throughout the day sometime around 11.04 - about a year ago. I see that F17 has tried to followed suit, but for some reason the implementation does not appear to function correctly. It's neat eye candy and although not an important function of the OS, if others can do it successfully - why not Fedora?
The wallpaper just stays on the classic fedora background and does not update.