Groovy Arcade Linux is an up to date GNU/Linux system, in 64 or 32 bit liveCD/liveUSB versions. It can be installed from the LiveCD onto the hard drive, or booted from a USB flash drive.
It has the current bleeding edge Linux DRM with Kernel Mode Switching and includes patches to allow 15Khz operation for Arcade Monitors and NTSC/PAL TV output. It uses the newest versions of Xorg so that the Vsync works with OpenGL without tearing and running with the vertical refresh rate of the monitor. It uses AdvanceMenu or WahCade as a frontend. It uses a custom C program named SwitchRes that utilizes Xrandr and a custom modeline generator to dynamically mode switch to the most optimal resolution for emulation on an Arcade Monitor or other monitor types.
Basically everything is just about done for you in the LiveCD and you can enjoy almost flawless emulation, depending on your Arcade Monitors capabilities, and not have to do much technical setup or work at building things from source.