Interesting. On a similar topic, I've noticed that some companies where I've worked as an employee or consultant, they have a policy of ALWAYS turning computers off at night, whereas others have a policy of NEVER turning them off.
I know that in some cases they are told to leave them on so that office automation can run scans, updates, etc, but I often wonder in general what is the best policy.
In respect of my own computers, I tend to 'hibernate' them overnight or when going out, but when I'm away for more than a day or so then I switch them off. I also restart them once a week or so as I believe it clears out a lot of unwanted files etc.