I'm sure to get some flack due to the Arcade1Up cabinet but wanted to share my build for others that are on a lesser budget, want to do it in stages but have the option to upgrade while still keeping most of your hardware investment. I still have a few things left to do (coin doors, 20" monitor)...
Current Build: Dell PC running LB, LEDBlinky, various emulators
Custom Control Deck
Ultimarc: Ultimate I/O, (2) U360 w/stiffer springs, longer shafts, and servo motors, Gold Leaf buttons
Groovey Game Gear: TurboTwist2, heavier knob, 7-inch steering wheel
Dedicated power supply, LED lights in cabinet, various other stuff...