These days the default plug is becoming 5vDC in the USB-1 configuration and the manufacturers are integrating that into "mains" receptacle devices. I have a few of those.
I though of running 12vdc circuits in a remodel but voltage drop becomes a problem when the wires get very long. I do have a 12v supply in the garage as part of my pool and spa controller and I tapped off of that for a few other things. That is just a terminal block with spade connectors. Originally it was a transformer/regulator supply but that got replaced with a switcher.
