Why be bovvered?
Companies will start worry about being 'green' if they see the cost of energy as being too high - obviously you can save money by saving electricity, but often the cost of implementing change is higher than the saving (both in money & energy), and none of the legislation proposed is likely to change that.
And you can't really force up the cost of energy to change behaviour, the market has already increased the cost of energy enormously, but people still use just as much, which gives a hint that additional taxation wouldn't do much either.
Buying energy from 'green suppliers' is pointless - there isn't enough genuine 'green energy' to go around, and carbon offset is at best unproven, so all you're really doing is paying more for the same product that isn't actually green at all.
As for turning equipment off - I can state from both personal and engineering experience that power cycling is a great way to kill equipment. Of all the hardware I've had that's died in the past few months, it's turning it off that finally killed it, usually power supplies that would run fine if left active or on standby, but couldn't restart if shut down completely. Given the relative environmental impact of manufacturing then prematurely scrapping equipment, vs. the impact of leaving it on (esp. if on standby), the balance really has to go towards leaving stuff turned on full time, or on standby, until it's time for scrapping.
Of course most of the green lobby looks for the 'obvious' solution, especially if it fits their world view; whether the obvious solution is the best one is another matter.
Better to improve energy efficiency through the normal equipment replacement cycle, and reduce heating/cooling costs, and turn off excess lighting than to jump on the bandwagon of 'green' energy and turning everything off at night.