Interesting thread - s'wot I do....
I leave mine on but turn the 2 monotors off because we run a 24 x 6-and-a-bit newspaper printing business. I'm on 24x7x365 remote support and need access to my PC cos its already got most of what I need running on it, but the office users turn their PCs off overnight and we use a NAS for file storage that gets full backup over night to one of 2 500GB removable HDDs - more space than tape, faster than tape, and SOOOO much CHEAPER!. RAS/VPN and RDP sessions do not a monitor need. Turn it off when you go home. Use Wake-on-LAN if you have to.