I'm putting a sticky post here, mostly for my reference, so that I don't forget to get around to fixing these things. If you find something else wrong, post below in the forum, and I'll add to this thread as necessary.
*** Beatmania ***
Lights are not correct. Should be both red and blue lights. Left and right lights should be synced separately. Need to get new pics. (Thanks HowardC for mentioning this).
*** Playchoice Single Monitor LED ***
Not hooked up. Listed at MAMETesters: http://www.mametesters.org/view.php?id=2076
RELAX and just have fun. Remember, it's all about the games.