I think its ok, to let the ogg-codec be seperate from the
game-files, as its a "public" plugin. So you can use ogg, and put the installer for
the codec into the "engine" folder.

Some small recent games of mine:
Griefer 4k http://damocles11.byethost9.com/griefer4k.html
Kobold 4k http://damocles11.byethost9.com/kobold.html
Cave 4k http://damocles11.byethost9.com/cave4k.html