This cabinet is being built to run 4-way MAME roms, NES and Sega Genisis. I'm powering it with a Raspberry Pi 2 B running the RetroPi frontend. I'm using the GPIO driver from Adafruit to allow the joystick and buttons to plug directly into the RPI. This driver does keyboard encoding, which I found much easier to work with than Joystick encoding.
I have a $3 power strip wired directly to the input plug on the cabinet. There's a 12v wall wart to power the amplifier and marquee led, a 5v wall wart to power the RPI and the monitor is plugged into 110v directly.
It's an HP 1825 18.1" monitor, which I think weighs more than the rest of the cabinet (14lbs monitor).
I'll take some interior pictures tonight, but there's not much to see, it's a huge empty space