One way to keep your house really clean- don't forget to change your furnace filters often. My mother in law's house was always so clean and the walls stayed so clean even though they didn't paint very often. I found out the secret was they changed their furnace filter every month. You really don't need to do it that often with the super filters they make now but every few months is good. You can tell by checking it. I usually write it on the calendar so I don't forget.
Another tip I just saw on t.v. – use a piece of cheesecloth (or special filters from the Dollar store) inside your air vents. It traps the dust from the furnace. I also stick the vacuum attachment down the furnace vents once in a while.