#1 - Your question has nothing to do with having a good gaming rig and you know that. Your purpose in title was simply to justify your posting in the "Building, Buying, or Upgrading High Performance PC Systems" thread because it is the most looked at/popular section.
#2 - I turn my computer off at night. There is no reason to leave it running when it's not in use.
I leave my computers on weekends on 24/7 and on weekdays it is turned on when i get home at 5:00, and then shut off in the morning (it is on all night folding)