Environmental Costs of Computer Use?

arhines asks: "I'm working on a little research project to figure out what the environmental cost of heavy technological reliance is, and want any suggestions Slashdot has for factors to consider. My school has started requiring students to own and use laptops in all of their classes, under the pretext of saving paper. Having read about the problems with computer recycling on Slashdot, I've become suspicious of the true effect of having several hundred computers thrown out each year. What statistics should I focus on, and are there any definitive studies on the topic you could point me to?"