I recently discover this and man this guy has talent! Here's just a few song I listen to and just listen to this awesomeness.

Dire Dire Docks Acapella - Super Mario 64
http://www.youtube.com/watch?v=GBBlLeqKaf4&list=PLX2MjbJ6GIceq8YbAPJ0ExF_yRUafQkLG&feature=share&index=55

Sonic - Green Hill Zone Acapella
http://youtu.be/NbVZPu_JM6I

Mega Man X - Storm Eagle Acapella
http://youtu.be/W54gF6QxeqM

Super Mario World - Overworld Theme Acapella
http://youtu.be/ndiD8V7zpAs

Final Fantasy VII - Victory Fanfare Acapella
http://youtu.be/JPBRbIvs5lc

Pokémon theme parody acapella - 'Try to catch a few' ft. Dookieshed
http://youtu.be/zItKxjn57YQ

Chrono Trigger - Corridors of Time (Zeal Theme) Acapella
http://www.youtube.com/watch?v=JtKCt8Afk9s&feature=share&list=PLX2MjbJ6GIceq8YbAPJ0ExF_yRUafQkLG&index=48