There's an entirely sensible campaign now in the UK to encourage people to switch off appliances left on standby, saving both greenhouse gas emmissions and money.
I try hard to be environmentally friendly - low-energy light bulbs and appliances, using cycling and public transport etc, but I confess my computer CPU isn't switched off from one week to the next. (Although I do switch off the screen.)
The problem is it takes so long to fire it up again. And it seems strange that this problem hasn't been solved - it is one of the primary annoyances of computing. And it also drives us mad at work, where an average of several crashes per computer per working day (usually right on deadline) wastes huge amounts of time in restarting. (I used to believe the claim that Apples never crashed - Hah!)
But finally, it appears, there is a solution in sight. About time!