EggXpert

Here is the power supply I may be using:

PC Power & Cooling S75QB 750W ATX12V / EPS12V Power Supply - Retail

 Kind of a newbie question, but does this power supply run 750W no matter what?  For example, if the system is idling, would this PSU still be pumping 750W into the system.  I live in a small village in Alaska and energy prices are roughly double the national average here, so if it does 750W continuously , it would quickly turn into a hefty electric bill.  The computer wouldn't need that much power off the start, but might need it in the long run, when I put another GPU and eventually another CPU into the system, so it might be financially better to buy a bigger power supply then, if it does consume that much power constantly.  If you want to look at the system build here's the link: $1200 gaming rig

 Anyways, thanks in advance and I would really appreciate any help I can get.
 

No, the power rating of the PSU in watts is the maximum power it can supply to your system. It only uses what your system needs.  So if you want a power efficient computer, buy power efficient components (CPU, graphics card, one hard drive instead of several, etc. etc.)