I have heard about the Roomba (http://en.wikipedia.org/wiki/Roomba). My sister bought one for around $350--I think instead of her doing the vacuuming, the Roomba patrols the house for any dirt and picks it up -too bad, it can't pick up scattered dog toys ;( or I would have gotten one myself ....Anyway, we also got our own version of the Roomba.
She is 68 lbs, with shiny & silky black coat & very food-motivated. She neatly eats her food and cleans up any spills. She even waits for messy Louie to finish so she can clean his spills....and she constantly picks up any dog biscuit crumbs that may have been left/dropped by Louie...amazing cleaning powers, huh!