Environmental cost of computing equipment
This article at Wired raises some interesting issues: Wired News: Short-Lived PCs Have Hidden Costs In my mind, it is an argument against a laptop computer purchase. It is much harder to upgrade a laptop than it is a desktop machine. It also is a case against distributed computing projects like Distributed.net, or seti at home that provide an incentive to leave your computer on all the time (to help contribute to the computing effort).