I know most games here talked about are the classics, but considering there are still some companies putting out quality arcade games (on simple PCBs, with 2D sprites, and all the good shit) I figured I'd post my recent Xmas gift to myself.
ESPGaluda II: Cave's follow-up to their manic shooter ESPGaluda (duh). Currently only in the Japanese arcades, but will hopefully get a PS2 port sometime around Summer.
If you hurry to hameko.net, you can see the game in action by downloading the videos: Click me
#3493: Stage 4 boss
#3453: Stage 6
#3379: Tutorial Bug & Stage 1
#3365: True Seseri (special boss of Stage 5)
Official Website
The SH3 PCB (this is Mushihime-sama I found on google, but it looks the same).
Everything but the board:
The poster that came w/ it (2 meters tall!)