Some Neo-Geo developers put quite a bit of effort into their attract modes and the results are pretty amazing considering the capability of the hardware. Here are some of my favorites.
To get the most out of these I really recommend running the games in an emulator (with blurry filters turned off) or better yet the real hardware, as Youtube compression makes sprite work look terrible.
Money Idol Exchanger
The King of Fighters ‘97
Blazing Star
Waku Waku 7
The Last Blade 2
Fatal Fury 3
Real Bout Fatal Fury 2
Captain Tomaday
Breakers
Magical Drop III
The King of Fighters ‘98
Neo Bomberman
Pulstar
Kabuki Klash - Far East of Eden