These are always fun, but don't address the need that many game developers (ok, at least "I") have - the need for detailed backgrounds - preferably ones that can mesh well with each other. That can really help set the "world" for the player, and while a developer can often do their own sprite artwork, backgrounds tend to be an art to themselves.

I usually end up going to either one of my 3D tools or my photographs, and then playing with filters in Photoshop to get an artistic look that isn't too jarring.