You think of your cat as a material object? Sick.
Well, I guess my laptop. Though not the most pricey, I am very much used to it for most of my productivity (that would be my laptop running Windows 7). Other contenders are my TV, my Xbox (or Sancty's XBox, whatevs) and my tower computer set up.
Do you think there are things that are impossible for you to achieve mentally even if you set your whole mind to it?