I recently picked up through my company's employee purchase program a nice HP 318 camera. It is only 2.31 megapixel, but it works out of the box with debian (thanks gphoto2 and gtkam!), has a CF slot so with a 256M card it can hold almost 300 pictures at its highest resolution. The kids and I have been going crazy taking pictures of pretty much everything.
Picture of our living room rug -- suitable for screen background (click t o download)