Powering up and powering down is generally the most stressful time for electronic components. Although you MIGHT think you are being green unplugging and re-plugging all that stuff (or just switching it off and on!), all it takes is for one of them to fail, and you have now lost any advantage you might have slowly garnered, because you have to go and buy something new, which has a MUCH larger footprint than the little power you used in standby...

It ain't easy being green...