Turning computer off vs. letting it run idle when not in use? Which is better?

[Astray]

I would leave my computer on as much as possible.

Each and every shutdown/poweron means that power has to be forced through the entire system again, which means more of a chance for the hardware to fail.

 

[AdamSnow]

I leave mine on 24/7/365 as well...

I just have Windows turn off my monitor after 10 minutes, and turn off hard drives and everything after 30 minutes... I have done this for years, never had a problem.