We make it a goal any time we walk away from our laptop+external monitor setup to not only put the system to sleep, but also to turn off the monitor to save energy. It's a small step, but we're all about promoting small steps alongside the big ones; they're all important. But it is also a practice all too easy to forget when running to check on your pasta or catch a 10 minute clip on G4. So we're big fans of this new technological feature from Eizo Nanao which integrates a motion sensor to provide active power only when the user is in front of the monitor, powering down to power save mode when nobody is detected for 40 seconds or more...
The 23-inch FlexScan EV2303W is capable of 1920 × 1080 native resolution and a modest 1000:1 contrast ratio; the 20-inch FlexScan EV2023W sports 1600 × 900 native resolution and 3000:1 contrast ratio. For now, our Dell 24" screen will just have to depend upon our good sense and memory for any energy saving gains, but we hope to see similar technology that mimics hybrid car "fuel" saving systems like this in more home appliances and other items that are almost always on.
More information over at Eizo.