I dont leave my main computer on overnight, however I do leave some computers that are my personal property on overnight
Server.mayhew.ca (DNS SERVER and PDC for my house, stays on 24 / 7, personal property)
techvideoserver.hwdsb.on.ca (200 Gig fileserver, only used during school hours, school property but I manage it)
mumbojumbo.porkchop.ca (Remote access machinne setup for remote access into the network, my personal property)
Mobile.mayhew.ca also stays on 24 / 7 but is usually in sleep or hibernation.