I hate to do this one, because it means that after a certain amount of time, my laptop will go to sleep, and consequently I will be disconnected from IRC and other "always on" networking features. However, it's time to make some changes.
I've set my laptop to power down the display after 15 minutes of inactivity, and to power down the whole computer after 1 hour of inactivity.
Apple says that its laptops are Energy Star compliant, so that helps. I'll also try very hard to turn my work computers off when they're idle, such as over a weekend when they're not doing any jobs.
Pocket: 6, Planet: 10, Win-win: 28