Also to mention, computer lifespan is much greator if you don't always have it on. Fans, hard drives, components, etc. only last for so long. And with overclocking, the lifespan is nearly cut in half for some components.
I'm not saying your computer is going to blow up in a year, just saying it would last longer in the long run. So, now, add them up:
$120/yr or ~$200/yr (for power sucker)
~$1500 new computer every ~5 years or even less than 5 years!
=
Alot of money!
Don't get me wrong, if you're wiping your *** with $100 dollar bills then leave it on all the time!