I struggle with this for my personal computer. The TV-computer combo shuts off the monitor (triggers the tv to shut off when there is no input) after an hour. An hour after that it's suspended, works well.
My personal computer though, sometimes I shut off the monitor, most of the time I let it run for the day completely powered. I have yet to set any type of shutdown or standby because typically I use it more than I do my tv (work, gaming, videos, etc on the comp). I know there's some power conservation I need to consider for motivation, I have no security concern atm with my standard main account and everything private is layered so inaccessible.
tl;dr
what's everyone else's setup like for when they walk away from the computer?
My desktop PC stays on through out the day, but I turn it off when I’m sleeping, mostly because it flashes the power button LED in sleep mode, which sometimes prevents me from sleeping. I usually turn of the monitor for the same reason (LED button stays on).
My macbook is set to sleep/lock itself after some period of inactivity, and when I’m done for the day, I usually just close it. The only time I fully turn it off is when I’m traveling and trying to save as much battery as I can.