Bluematter.

Since it's invention in 1989, Apple-Cinnamon Cheerios have added about 0.002 percent to our welfare, meaning that if they had never been introduced, then we would need 0.002 percent extra income to feel just as well off.

For minivans that number is 0.029 percent, and for satellite TV it's 0.035 percent.

What about the personal computer? Since its introduction in 1977, the price of a PC, when advancements are factored in, has dropped 700 times, according to Jeremy Greenwood of the University of Pennsylvania and Karen A. Kopecky of the University of Western Ontario.

The two researchers say that our welfare has been improved by about 4 percent thanks to the PC revolution -- or about 2,000 times more than Cheerios. (pdf)