Contribution 1
Sure, alot of the newer arcade games are cool. But I think Pac-man was the best of all time. Easy to learn.. good challenge and replayability. Hell, even grown-ups knew how to play Pac-man (and many enjoyed it). I even see the table top version of Pac at pizza parlors sometimes. Pizza and Pac-man go great together by the way. :D

Contribution 2
Personally, my favorite arcade game of all time is Golden Axe. Sure, it may be one of many side-scrolling fighting games, but Golden Axe is more intricate with dragons and wyverns to ride, and magic to command. I always thought it was cool to dash really fast towards an enemy and then jumping really high in the air an landing on an enemy and crusing his head with your weapon.

Contribution 3
Excluding Neo Geo games (which are kinda both 16-bit console and arcade), I have to admit one of my favorite arcade games was Magic Sword. The SNES version was too watered down for my taste, but aside from the new 3D Gaunlet, it's the coolest looking side-scrolling fantasy game I've played to date. Hack-n-slash is kinda boring, but the variety and music keeps you wanting to see the rest of the place.
I just wish the action wasn't all inside a tower and it had cinema scenes (a la Ninja Gaiden). That could rock!

Contribution 4
Incorrect, the Neo wasnt' 16 bit it was pure arcade, the console was just a miniature arcade machine, and it was early 32-bit hardware anyway, not 16

Contribution 5
Wasn't the Neo Geo 24-bit?(!)