I'd recommend at least having player 1 & 2 coin-up and start buttons, a pause button, and an exit game button. Those are the buttons on my cab and I use all of them frequently. On the sides of my CP and semi hidden I also have a button to enter the mame config menu, an "enter" key button to be able to navigate the config menu, and the power button to the cabinet. I find those buttons are very useful, but are not necessary to have on the CP. If you have a keyboard tray then you wouldn't need any config buttons.